We estimated the length and age of maturation in little skate Leucoraja erinacea and winter skate L. ocellata based on samples of 1,884 little skate and 1,153 winter skate ovaries collected from Cape Hatteras, North Carolina, to Georges Bank. Two levels of maturity were recognized: onset maturity, which marks the onset of the allocation of energy from somatic growth to reproduction; and “functional” maturity, which marks the point when mature oocytes are released. Size at maturation increased with latitude in little skate, 50% onset maturity occurring at 42.5, 43.0, and 46.5 cm (total length) and 50% functional maturity at 43, 44, and 46 cm for the mid-Atlantic, southern New England–Georges Bank, and Gulf of Maine regions, respectively. Based on age estimates from previously published work, the age at which little skate achieve functional maturation ranged between 7.0 and 7.5 years for the U.S. northeast coast. In winter skate, no statistically significant regional differences in maturation rates were found. Size at 50% onset maturity was estimated to be 66 cm and at 50% functional maturity 76 cm for the U.S. northeast coast. In winter skate, onset maturity occurred at 9.5 years and functional maturity at 12.5 years. Thus, functional maturity in this species occurred 3 years after the onset of maturation, indicating that the species has a long adolescence before contributing offspring to the population.

We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies.

Scup Stenotomus chrysops, a commercially important marine species, are distributed from Nova Scotia to south Florida, and may represent morphologically distinct populations across their range. It was determined whether there were morphological differences between a North Atlantic Bight (NAB) population (41°N) and two South Atlantic Bight (SAB) populations (30°N and 32°N) of this species from April 2005 to July 2005, when the populations had formed spawning groups. Morphology was compared among populations by means of a geometric, landmark-based analysis of morphological and meristic traits for 180 individuals that were sexed and staged to maturity. A backward, stepwise discriminant functions analysis (DFA) produced a model that generated DFA scores that differed significantly between the NAB and SAB populations. Forehead and body depth dimensions differed among populations but not sexes. The DFA model predicted similar scores for 32 new NAB individuals and 31 new SAB individuals; however, scores were consistently underpredicted for the NAB individuals and overpredicted for the SAB individuals. We concluded that distinct northern and southern populations support a two-stock or two-species hypothesis; however, it is unclear whether this stock structure is related to reproductive or other life history traits. Either phenotypic plasticity or divergent selection may explain the morphological dissimilarities among these populations, but their influence on individual fitness remains unknown.

Waters of the northern Gulf of Alaska around Kodiak Island once supported the world's largest fishery for the red king crab Paralithodes camtschaticus. Commercial fisheries began at low levels in the 1930s, increasing rapidly in the 1960s to a peak harvest of 42,800 metric tons in 1965. Stock abundance declined sharply in the late 1960s, moderated in the 1970s, and crashed in the early 1980s. A commercial fishery closure since 1983 has not resulted in stock recovery. To improve understanding of stock dynamics, we examined spawner–recruit (S-R) relationships for the Kodiak red king crab stock. The shape of the S-R relationship helps describe average stock productivity at different stock levels, thus relating directly to fishery management objectives. Due to limited female data, we used only male data and two currencies of male abundance as a proxy for spawners: either (1) all males greater than or equal to 125 mm carapace length (CL) or (2) legal males (≥145 mm CL). Due to age uncertainty, we considered lag times of 5 to 8 years between reproduction and recruitment. Residuals from fitting a standard Ricker model were strongly negative for brood years from the mid-1970s to the mid-1980s and positive from the early to mid-1990s. A Ricker model with autocorrelated errors resulted in better fits with corrected Akaike's information criterion (AIC_c) values minimized for a 5-year lag using all males. Among model configurations, estimates of peak production ranged from 2.0 to 3.4 million recruits from a range of 11.3 to 37.7 million males. A model separating the time series into three productivity periods corresponding to different ecological regimes further improved model fit. Although abundances of both spawners and recruits have been less than 1.0 million males since 1985, depensation at low stock sizes was not detected. Future analyses will examine the contribution of ecological and environmental factors to crab recruitment.

In streams with sympatric populations of steelhead Oncorhynchus mykiss and coastal cutthroat trout O. clarkii clarkii (hereafter, cutthroat trout), life history descriptions and smolt production estimates may be hampered by misclassification of hybrids as steelhead or cutthroat trout. Additionally, important morphological and physiological differences between hybrid and non-hybird smolts are often unknown. Therefore, we assessed field classification and created classification models to quantify and reduce misclassification rates among migrating steelhead, cutthroat trout, and hybrid smolts. Field misclassifications of smolts with steelhead or cutthroat trout genotypes were low (1% and 2%, respectively). However, field misclassification of fish with hybrid genotypes was high, with 11% of the hybrids being misclassified as steelhead and 42% of the hybrids being misclassified as cutthroat trout. Hybrid smolts were larger, had lower gill Na , K -ATPase activities, and lower condition factors than steelhead but were similar to cutthroat trout smolts in these same measurements. Additionally, statistical classification analyses using morphological traits including subterminal jaw slash intensity, hyoid teeth presence, maxillary length, breaks of pigment along outer margin of adipose fin, condition factor, and migration date improved classification error rates of hybrids from 53% to 21%. In systems with sympatric populations of steelhead and cutthroat trout, we recommend a thorough evaluation of field-based identification methods with genetic techniques to assess the effectiveness of field-based classification in addition to examining important life history differences among steelhead, cutthroat trout, and their hybrids.

The main objective of this study was to use scale patterns to compare the early marine growth of the average pink salmon Oncorhynchus gorbuscha with that of fish from the same year-class that survived to adulthood to gain insight on critical periods for growth and survival. During 2001–2004, pink salmon that survived to adulthood were larger and grew faster than the average juvenile throughout the first growing season, indicating that larger, faster-growing juveniles experienced higher survival. Growth rate declined from mid–late June to early–mid-July for both juveniles at-large and fish that survived to adulthood. The adult survivors then grew at a faster rate than the average juvenile through September. Both the juvenile pink salmon population at-large and all cohorts that survived to adulthood grew at a faster rate during high-survival years than low-survival years from mid–late June to mid–late August. Greater variability in the growth trajectories of surviving adults was observed during high-survival years, potentially a result of diversified feeding or distribution strategies. This study supports findings that significant size-selective mortality of juvenile pink salmon occurs after the first growing season. Investigating the timing and magnitude of size-selective mortality on juvenile pink salmon during their first growing season is an initial step toward understanding the processes regulating growth and survival.

In order to better assess the ecological importance of offshore petroleum platforms for economically important groundfishes, we quantified the degree of site fidelity of 100 platform-associated individuals representing 15 species at three offshore platforms in the Santa Barbara Channel by means of acoustic telemetry monitoring. Thirty percent of the fish tagged were not detected after the first 6 d following release and were assumed to have died or to have immediately emigrated away from platforms. Degrees of site fidelity varied widely among individuals, among species, and between platforms. Of the most abundant species tagged (cabezon Scorpaenichthys marmoratus, vermilion rockfish Sebastes miniatus, widow rockfish Sebastes entomelas, copper rockfish Sebastes caurinus, and greenspotted rockfish Sebastes chlorostictus), widow rockfish showed a high probability of being detected at platforms over a 2-year period. Vermilion rockfish emigrated away from the shallower Platform Gilda (64 m) faster than vermilion rockfish tagged at the deeper Platform Grace (93 m). Ten tagged individuals (eight vermilion rockfish, one copper rockfish, and one lingcod Ophiodon elongatus) moved between platforms (range = 5–15 km) and/or natural habitat, although a majority moved from a shallower platform to a deeper one. These movements further support evidence that (1) many reef-associated rockfishes make ontogenetic shifts to deeper water and (2) shallower platforms export fishes faster than deeper platforms. There was no indication of seasonal emigration, but there was evidence for seasonal differences in activity for vermilion rockfish, widow rockfish, and greenspotted rockfish. Observed movements of fishes between platforms and natural reef habitat indicate that they can navigate between these habitats and that platform habitat, despite having higher densities of conspecifics, may be of higher quality to some individuals than natural reefs.

Populations of anadromous alewives Alosa pseudoharengus are declining throughout much of the species' range, particularly in southern New England, where fishery moratoriums have recently been instituted in three states. The alewife run at Bride Brook, a coastal stream in East Lyme, Connecticut, was studied from 2003 to 2006 to assess shifts in demography and life history. Annual censuses of abundance and sampling for size, age, and spawning history structure were conducted. These data were compared with similar data from 1966 to 1967 at this site. Recent alewife runs at Bride Brook featured lower abundance and younger, smaller fish that were less likely to be repeat spawners. The 1966 spawning run was dominated by repeat spawners of ages 5–7, while runs in 2003–2006 were dominated by age-3 and age-4 first-spawn fish. Mean length declined by 10% between 1966 and 2006. Alewives are also recruiting to the spawning run at younger ages and smaller sizes, indicating a shift in life history. The first-spawn portion of the 1966 spawning run was dominated by age-5 fish, while recent first-time spawners were primarily age 3. The shifts in demography and life history observed at Bride Brook are consistent with exploitation or predation concentrated on older, larger individuals in the population. The results of this study suggest recent increases in predatory pressure or bycatch mortality as promising hypotheses that merit further investigation.

The ability of fish to submerge after discarding is often used as a proxy for survival, but this practice underestimates total discard mortality because delayed mortality is overlooked. Fishery managers need a way to link “sink or swim” indicators, or variables observed during capture and release, with delayed mortality rates. We conducted a cage study of red snapper Lutjanus campechanus off the coast of Texas to estimate delayed mortality rates and to find factors that could link immediate and delayed mortality. Immediate mortality (17%) was predicted by the interaction of depth and the difference in temperature between surface and bottom waters. Lactate levels were also significant predictors of immediate mortality in fish whose blood was tested. Delayed mortality (64%) was predicted primarily by a condition index consisting of the presence or absence of injuries, symptoms of barotrauma, and fish behaviors immediately after capture. Specific categories included bleeding, protruding intestines, everted stomach, exopthalmia, the presence or absence of flapping and gilling behaviors, and problems with cage submergence. The majority of fatalities occurred within 24 h after fish were placed in the cages. Our mortality estimates indicate that red snapper discard mortality was significantly underestimated in the 2005 stock assessment for red snapper. The use of indices that relate the condition of an individual fish at capture to its probability of delayed mortality is an excellent method for linking immediate and delayed mortality and will likely be applicable to many species that are subject to catch-and-release fishing.

The spotted seatrout Cynoscion nebulosus is one of the most intensively managed finfishes in the Gulf of Mexico, due primarily to its importance as a sport fish species throughout its range. As a result, genetic divergence and patterns of gene flow have previously been assessed among designated populations of spotted seatrout by using various types of genetic markers in an attempt to provide meaningful data for delineation of management units. However, genetic data can be influenced both by contemporary gene flow and historical demography, and these processes can often result in similar genetic signatures. In this study, a nested clade analysis (NCA) was used to disentangle the effects of historical and contemporary processes on the distribution of mitochondrial DNA sequence haplotypes of spotted seatrout in the western Gulf of Mexico. The NCA was coupled with traditional F-statistics and a Mantel matrix procedure to compare the results of multiple analytical frameworks. Overall, genetic divergence among populations was low but significant and was highest between populations that were far apart geographically. Correlation between genetic divergence and geographic distance was supported by a significant Mantel matrix correlation coefficient, as well as two nested clades, which had distributions that correlated significantly with latitude. All three statistical procedures suggest that the genetic structure of spotted seatrout in the western Gulf of Mexico can best be described by continuous change and isolation by distance rather than representing discrete populations. These results are compared to the results of several previous studies using alternative types of genetic data and analytical procedures and are also used to put current management strategies for spotted seatrout into a genetic context.

We tested the overwintering capability of young-of-the-year (age-0) windowpanes Scophthalmus aquosus to determine if there are cohort-specific differences in growth and mortality. We conducted a laboratory study at ambient estuarine winter temperatures from 9 November 1995 to 22 April 1996 with two cohorts (spring-spawned cohort: 83–140 mm total length [TL]; fall-spawned cohort: 15–37 mm TL). We hypothesized that (1) among individuals within both cohorts, winter growth rates would be low compared with summer growth rates; and (2) overwinter mortality rates of the smaller, fall-spawned fish would be higher than those of larger, spring-spawned fish due to size-selective mortality. Under ambient winter temperatures (−2.0 to 14.0°C) with daily, ad libitum feeding in the laboratory, growth rates were low but positive for the fall- and spring-spawned fish. Overwinter mortality occurred in both cohorts but was higher for the fall cohort than for the spring cohort (75% and 31%, respectively). Within the fall cohort, mortality was size selective, with reduced survival of individuals smaller than 24 mm TL. Within the spring cohort, there was no evidence of size-selective mortality. We concluded that the first winter of life may be an important mortality bottleneck for both cohorts of age-0 windowpanes in the Middle Atlantic Bight but that mortality patterns are cohort specific and may be determined by different combinations of factors, such as fish size at the start of winter, the magnitude of water temperature decline between fall and winter, and the frequency and duration of extremely cold water temperatures. Thus, overwinter mortality during the first winter of life may influence the population dynamics of the windowpane and other multimodal spawners inhabiting the Middle Atlantic Bight.

Despite the large number of marine recreational anglers in the United States, there exist few opportunities for individuals to contribute self-reported effort and catch data directly to fisheries managers. Successfully implemented data collection programs based on self-reported information have been able to provide scientists with additional indices for comparisons with existing fisheries data sets and to increase angler participation and confidence in the fisheries management process. Limitations to self-reported data aside, the lack of a portable, electronic reporting device for the average angler has hindered development of new survey methods. We have developed a simple but fully customizable reporting method by which users can submit basic effort and catch information to an online database via text messages from mobile phones. To evaluate this new approach, we asked captains on behalf of six marine for-hire operations to send a text message to document effort, catch, and disposition of catch by species at the completion of each for-hire trip. Report submission was facilitated by RECTEXT, a compact syntax we developed to allow users to submit information within the technical limitations of a 160-character text message framework. During the course of the 4.5-month evaluation, participants submitted 128 trip-level reports that described 1,957 finfish interactions. Results and feedback from participants indicate that the approach is easy to use, is cost efficient, and allows for real-time reporting of information directly to an online database. In addition to the electronic angler diary application described here, we suggest that future evaluations of this approach be applied to tournament data collection, as the real-time nature of reporting and the organized structure of tournaments may provide a mechanism to both interact with all registered anglers and facilitate design of an unbiased sampling protocol for validating the self-reported data.

Catches of 19 marine fish species from the eastern and western portions of the North Pacific Ocean during 1970–2004 were examined to determine whether there was synchrony in their responses to the generally accepted climate regime shifts that occurred during that period. Catches for these species represented approximately 55% of the total fish catch in the North Pacific in the 1990s. Five distinct groups were apparent in the data, and each group exhibited a different response to the climate regime shifts of 1977, 1989, and 1998. Some species appeared to have responded only to the regime shift in 1977, others responded only to the shift in 1989, and a few species responded to both. The trends in the time series of catches for these five groups were not random, and shifts in catch generally coincided with regime shifts as identified by the Pacific Decadal Oscillation and other indices of climate change. Although this study examined the relationship of fisheries to trends in climate, there is an obvious linkage to the population dynamics of a particular species. Understanding how climate affects these linkages may help improve our ability to reliably forecast population and fishery trends in the future.

Current fisheries management policies generally require an assessment of stock status, which is a difficult task when population and fisheries data are limited. Three simple metrics based on catch length compositions (i.e., that reflect exclusive take of mature individuals, P_mat; that consist primarily of fish of optimal size, the size at which the highest yield from a cohort occurs, P_opt; and that demonstrate the conservation of large, mature individuals, P_mega) can be used to monitor population status relative to exploitation. The metrics (collectively referred to as P_x) were intended to avoid growth and recruitment overfishing, but there was no quantitative linkage to stock status and calculation of future sustainable catches. We attempt to make this connection by exploring the relationship of P_x measures to fishing mortality and spawning biomass (SB). The relationships are compared specifically to the current target reference point (0.4 times the virgin, or unfished, SB [SB₀]) and limit reference point (0.25SB₀) used for the U.S. West Coast groundfish fishery by using simulations based on a deterministic age-structured population dynamics model. Sensitivity to fishery selectivity, life history traits, and recruitment compensation (steepness) is explored. Each P_x measure showed a wide range of possible values depending on fishery selectivity, steepness, and the ratio of the length at maturity (L_mat) to the optimal fishing length (L_opt). Although the values of P_x may be compatible with sustainable fishing, these values are not always sufficient to ensure stock protection from overfishing. Moreover, values for P_x cannot be interpreted adequately without knowledge of the selectivity pattern. A new measure, P_obj (the sum of P_mat, P_opt, and P_mega), is introduced to distinguish selectivity patterns and construct a decision tree for development of stock status indicators. Heuristic indicator values are presented to demonstrate the utility of this approach. Although several caveats remain, this approach builds on the recommendations of previous literature by giving further guidance related to interpreting catch length composition data under variable fishery conditions without collecting additional information. It also provides a link to developing harvest control rules that inform proactive fisheries management under data-limited conditions.

Queenfish Seriphus politus were collected at coastal power plants from San Clemente to Ventura, California. Power functions best described relations between otolith length, width, or weight and either standard length (SL) or total body weight. The length–weight relationship was described by the following equation: weight = 10⁻⁵ × SL^3.09. Individuals were aged to 12 years by using sagittal otolith sections. Females grew at a significantly faster rate than males. Both sexes reached 50% maturity by 100 mm SL, or shortly after age 1. The total annual instantaneous mortality coefficient was estimated at 0.42. Catalina Harbor (on the windward side of Santa Catalina Island) and Ventura were the most populous sites based on gill-net catch per unit effort from 1995 to 2006. Juvenile and adult queenfish populations have declined since 1980 in a significant relationship with nearshore plankton biomass. Larval queenfish densities recorded in King Harbor (Redondo Beach) have declined since 1987. Long-term recruitment estimates indicated peak recruitment prior to 1976, with three subsequent downward baseline shifts.

Estuarine food webs are highly variable and complex, making identification of their trophic pathways difficult. Energy for the food web of the San Francisco Estuary is thought to be based largely on in situ phytoplankton production, but little attention has been paid to littoral habitats, where other energy sources may be important. We analyzed the stomach contents of over 960 juvenile fishes and the stable carbon and nitrogen isotope ratios of these fishes and their potential food resources in pelagic and littoral habitats from the tidal freshwater area of the estuary. The mixing model IsoSource was used to examine energy sources important to consumers. Our results show evidence of two predominant food web pathways. Pelagic fishes and some littoral fishes showed strong dependence on a zooplankton–phytoplankton trophic pathway. However, the majority of fishes in littoral habitats had diets and carbon isotope ratios consistent with energy arising from submerged aquatic vegetation and epiphytic macroalgae. IsoSource revealed that the overall majority of nutrition of littoral fishes originated from consumption of grazer amphipods. Examining both stable isotopes and stomach contents allowed us to identify a food web with contributions to resident fishes that had been previously underestimated in the estuary. This study provides insight to how estuarine food webs have changed over the last few decades and highlights why the functions of habitats must be understood for effective restoration planning.

We investigated the utility of a fishery-independent trawl survey for assessing a potential multispecies shark nursery in Georgia's nearshore and inshore waters. A total of 234 subadult sharks from six species were captured during 85 of 216 trawls. Catch rates and size distributions for subadult sharks and the ratio of neonates to juveniles were consistent among areas. The highest concentrations of subadult sharks occurred in creeks and sounds. Species composition varied among areas. The Atlantic sharpnose shark Rhizoprionodon terraenovae was the most abundant species in sound and nearshore stations, whereas the bonnethead Sphyrna tiburo was the most abundant species in creeks. The aggregate of other species occurred with higher frequency in the sounds and nearshore. Sampling characteristics of the trawl survey were compared with those from a fishery-independent longline survey of subadult sharks to assess the similarity of the two gears. A total of 193 subadult sharks from seven species were captured during 57 of 96 longline sets, whereas 52 subadults from four species were captured during 20 of 48 trawls. Selectivity and efficiency differed between the two gears. The trawl had lower catch rates, caught smaller sharks, and encountered a different suite of species than the longline. General seasonal trends in relative abundance also differed between the two gears; the longline showed an increasing trend in abundance, whereas the trawl showed a stable trend. Although trawls were not found to be efficient for sampling subadult sharks from most species, they can be a useful source of supplemental data.

Responding to the need for management of California's nearshore fisheries mandated in state law by the Marine Life Management and Marine Life Protection acts, the San Diego Watermen's Association (SDWA), which includes divers that target local red sea urchins Strongylocentrotus franciscanus, initiated a community-based data collection program in 2001. In collaboration with independent scientists and biologists from the California Department of Fish and Game, the SDWA developed an ongoing program to gather, organize, and analyze both fishery-dependent and fishery-independent data on the local red sea urchin fishery. The goal of the program is to collect data that will support periodical stock assessments needed for sustainable management of existing nearshore fisheries (including red sea urchins) as well as the kelp forest ecosystem on which these fisheries depend. Here, we discuss sampling designs, methods for determining data quality (bias and precision), and methods for detecting change, and we provide some examples of results from the ongoing community-based data collection program. We also report on (1) the design and implementation of scientifically valid sampling protocols; (2) data quality assurance and control collaboratively conducted with scientists and resource agency biologists; (3) calibration studies to determine accuracy and precision and the magnitude of detectable changes in red sea urchin populations; and (4) visualization and dissemination of data and results and incremental changes in protocols that would facilitate the monitoring of associated biological communities. Finally, we discuss keys for success in this cooperative-based data collection program and its implications for stock assessment and management of the red sea urchin fishery in California.

There is an increasing expectation for decision makers to use robust scientific advice on the status of exploited fish stocks. For example, Australia has recently implemented a harvest strategy policy for federally managed fisheries based on limit and target biomass reference points. In common with most fisheries jurisdictions, however, Australia has many data-poor species and fisheries for which biomass estimates are unavailable. Consequently, the challenge for those tasked with providing management advice for Australian fisheries has been reconciling the need to achieve specific risk-related sustainability objectives with the reality of the available data and assessments for data-poor species and fisheries. Some general recommendations regarding how to achieve this balance are drawn using case studies from two multispecies trawl fisheries. The lack of data on which to base quantitative stock assessments using population dynamics models does not preclude the development of objective harvest control rules. Evaluation of harvest control rules using technical procedures (e.g., the management strategy evaluation approach) is ideal, but implementation before rigorous testing is sometimes a necessary reality. Information from data-rich species and fisheries can be used to inform “assessments” for data-poor species and thereby develop appropriate control rules. This can be done through formal methods, such as the “Robin Hood” approach (in which assessments from data-rich species are used to inform assessments of data-poor species), or less formally by grouping species into “baskets” and basing management decisions on one appropriate member of the group. Stakeholder knowledge and buy-in to the process of developing appropriate harvest strategies are essential when species or fisheries are data poor. Use of this information, however, needs to be constrained by policy decisions, such as prespecified performance standards. There will always be a trade-off between the cost of data collection and the value of a fishery; in this article, we highlight that this trade-off does not have to be a major impediment to the development of realistic and sufficiently precautionary control rules for the management of data-poor species and fisheries.

The use of fisheries-independent trawl survey data to estimate fish abundance in shallow coastal systems can present challenges for producing reliable population estimates. We used hydroacoustic and trawl data to estimate the catch efficiency of a demersal trawl that is presently used in surveys to support stock assessments in Chesapeake Bay, USA. Specifically, we determined the efficiency of catching Atlantic croakers Micropogonias undulatus and white perch Morone americana, two of the most common species captured in the trawl survey. Monotypic hauls (>90% by abundance) from 2003 to 2004 were used to estimate catch efficiency, defined as the ratio of the observed catch to the number of fish encountered by the trawl, which we estimated by deploying a scientific echosounder directly in front of the trawl net. The catch efficiency estimates ranged from 0.18 to 1.26 for Atlantic croakers (n = 29 tows) and from 0.11 to 0.60 for white perch (n = 7 tows). For Atlantic croakers, Spearman's rank correlation between the total and predicted catch was 0.53. A post hoc analysis of the Atlantic croaker efficiency estimates based on general linear modeling suggests that trawl efficiency is a function of fish behavior, gear geometry, and habitat. Efficiency declined with increasing fish density and increasing trawl width; to lesser extent, an increasing proportion of fines in the sea bed and decreasing depth were also associated with declines in efficiency. We conclude that because catch efficiency is variable, the trawl should be integrated with hydroacoustics to obtain improved population data.

This article summarizes catch data for sharks collected by fishery observers during two periods (1995–2000 and 2004–2006) in the Hawaii-based pelagic longline fishery, which targets swordfish Xiphias gladius in the shallow-set sector and bigeye tuna Thunnus obesus in the deep-set sector. The blue shark Prionace glauca was the predominant shark species caught throughout the study period (84.5% of all sharks). Five other species (bigeye thresher Alopias superciliosus, oceanic whitetip shark Carcharhinus longimanus, shortfin mako Isurus oxyrinchus, silky shark C. falciformis, and crocodile shark Pseudocarcharias kamoharai) were relatively common (1.0–4.1%). Two major developments affected shark catches in this fishery during the study period. The first was the prohibition in 2000 of shark finning under most circumstances. The second development was that management measures were taken in 2000 and 2001 to protect sea turtles (leatherback sea turtles Dermochelys coriacea and loggerhead sea turtles Caretta caretta) and these measures included a closure of the shallow-set (swordfish-targeting) sector for more than 3 years. The closure caused decreases in shark catches because the shallow-set sector was typically characterized by high catch rates. The shallow-set sector was reopened in 2004. Comparisons of nominal catch per unit effort (number of sharks/1,000 hooks) revealed significant differences in catch rates between the two fishery sectors and the two periods. Blue shark and shortfin mako catch rates were significantly greater in the shallow-set sector than in the deep-set sector of the fishery, whereas the opposite was true for the deeper-dwelling bigeye threshers and crocodile sharks. Catch rates for the blue shark, oceanic whitetip shark, bigeye thresher, and crocodile shark were significantly lower in 2004–2006 than in 1995–2000. For the blue shark in particular, the combination of reduced catch rates, the finning ban, and an apparent capacity to resist the stress of capture on longline gear resulted in low (4%–5.7%) minimum mortality estimates. Therefore, we conclude that the Hawaii-based pelagic longline fishery has made substantial progress in reducing shark mortality.

Estimation of harvest rates is often a critical component of fishery stock assessment and management. These assessments are often based on catch-at-age data sets generated over many years, but estimates of instantaneous fishing mortality (F) can also be obtained from a shorter-term tag return study. We conducted a 2-year tag return experiment to generate direct estimates of F for southern flounder Paralichthys lethostigma in a North Carolina estuary. The southern flounder supports lucrative commercial and recreational fisheries within the state and has experienced heavy fishing pressure for more than a decade. During 2005 and 2006, fish were captured and tagged with the assistance of commercial harvesters in the New River estuary. Tag returns were used to generate monthly estimates of F, which demonstrated a clear seasonal pattern that was consistent between years. Several important assumptions of the tag return model were accounted for through the use of double-tagged individuals, the distribution of both high- and standard-reward tags, and the completion of an independent controlled experiment to evaluate mortality related to tagging. Annual estimates of F exceeded the short-term management target in both years. Residual patterns suggest that the estimates may actually have been biased low, possibly due to delayed mixing of tagged fish. Thus, despite recently amended fishery regulations, F in the North Carolina southern flounder gill-net fishery still has the potential to greatly exceed targeted levels, which may delay stock recovery. Tag return studies can provide reliable (and nearly real-time) information about F and natural mortality as long as the experimental design addresses specific assumptions related to tagging-induced mortality, tag shedding, and nonreporting of tags.

Both natural scientists and economists commonly use quantitative data to create models of the systems that interest them and then use these models to inform fisheries management. Other social scientists rely on lengthier, descriptive texts based primarily on qualitative data to assess the human dimensions. To their dismay, fisheries social scientists find that much of their rich narrative with keen insights ends up filling pages that are neither read nor meaningfully integrated into decision-making in fisheries management. Nevertheless, what all scientists, practitioners, and managers want and need is information that will lead to a better understanding of the ecosystem (comprised of interdependent ecological and human systems) and therefore to fisheries management that benefits the whole system. Based on the belief that only a combination of high-quality quantitative and qualitative data will provide both the numbers and the context needed for success in ecosystem-based management, we discuss efforts to present social and cultural information in forms that are more familiar to those who rely on models for a representation of reality in the fisheries context. We point out how the designers of these models (or how we) think the models might be applied to fisheries management, noting how each model attempts to incorporate qualitative data to depict context essential for grounding the more commonly used biological and economic models. We also assess the benefits and limitations of these models, including the constraints on their development and use.

Collaborative fisheries research (in contrast to cooperative research) is based on the intellectual partnership between scientists and fishermen and is an effective way to collect data for stock assessments and to evaluate marine protected areas. Collaborative fisheries research is discussed in the context of co-management of marine resources and how it contributes to a more democratic form of fisheries management. Many benefits result from working together, including (1) the incorporation of fishers' knowledge and expertise into the management process and (2) the development of shared perspectives derived through science-based investigations on the status of marine resources. The California Collaborative Fisheries Research Program was formed in 2006 to participate in the monitoring of marine reserves established through California's Marine Life Protection Act. This program has shown that it can serve as a model for other areas that are trying to implement collaborative research and that collaborative research can greatly contribute to the realization of community-based co-management of marine resources.

Growth rates were estimated for recaptured Hawaiian spiny lobsters Panulirus marginatus tagged between 2002 and 2007 at Necker Island (23°30′N; 164°35′W), Gardner Pinnacles (25°00′N; 168°50′W), and Maro Reef (25°30′N; 170°45′W) in the Northwestern Hawaiian Islands (NWHI). The location and year-specific nature of the tag–recapture cruises enabled investigation of spatial and temporal variability in growth. Mean growth rates, estimated by using the von Bertalanffy and Schnute growth models and fitted via a maximum likelihood technique, differed between sexes and particularly among locations and years. Male lobster growth rates at Necker Island were, in general, one-third those at Gardner Pinnacles and one-half those at Maro Reef. Female lobsters exhibited the same pattern with less-pronounced differences. Maro Reef lobsters exhibited several abrupt, significant growth reductions among years, while Necker Island lobster growth rates increased significantly from 2004 to 2005. Model results also indicated substantial individual variability in growth. Neither density nor temperature could account for the differences in growth rates. No palinurid species studied to date has shown such spatial variability in growth, and only one panilurid species has exhibited similar variability on a temporal scale. Recognition of and accounting for the mean and individual variability in a life history trait of this endemic species will result in more accurate stock assessments and, ultimately, a better understanding of lobster dynamics and the NWHI coral reef ecosystem.

Freshwater flow can have a profound influence on the transport of larvae within large tidal estuaries, and tidal flow can transport larvae away from those estuaries. Our objectives were to (1) confirm that a combination of freshwater and tidal flows transported post-yolk-sac larvae (PYSL) striped bass Morone saxatilis from the Hudson River, New York, to western Long Island Sound (WLIS), a nearby nursery area, and (2) assess the effect of PYSL transported from the river on the abundance of juvenile striped bass in WLIS. This approach included (1) calculating an index of juvenile striped bass abundance in WLIS (WLIS juvenile index) for July and regressing it on an index of striped bass PYSL abundance for the Battery region of the Hudson River (Battery region PYSL index), which represented annual changes in the abundance of striped bass PYSL that could be transported from the river to WLIS, and (2) regressing a WLIS juvenile index for August on the WLIS juvenile index for July. The regression of the WLIS juvenile index for July on the Battery region PYSL index was significant and positive. The regression of the WLIS juvenile index for August on that for July was not significant. We confirmed that striped bass PYSL were transported from the Hudson River to WLIS by a combination of freshwater and tidal flows. Furthermore, in years when striped bass PYSL abundance and freshwater flow in the Hudson River were unusually high, striped bass PYSL transported from the Hudson River substantially influenced abundance of juvenile striped bass in WLIS during July but not August. The difference in abundance between months was apparently due to high natural mortality early in the juvenile life stage.

The British Columbia fishing industry and the Department of Fisheries and Oceans Canada introduced 100% monitoring of the commercial groundfish hook-and-line and trap fisheries in April 2006. The monitoring system includes cameras to capture video footage of hauling at the vessel's side, Global Positioning System-linked winch sensors on all boats, 100% dockside monitoring of piece counts and weights, and 100% retention of all rockfishes Sebastes spp. The system provides official estimates of total catch in pieces and weight (retained and discarded) through the fisher logs and dockside monitoring. Using catches of yelloweye rockfish S. ruberrimus as a test case, this study examined the accuracy of catch estimates produced during the third year of the program (April 2008 to March 2009). The analysis indicates that the overall monitoring produces accurate catch estimates of yelloweye rockfish. A key, and possibly unique, component of the catch verification was the derivation of an alternate estimate of total catch. This estimate was derived from the data that result from the video review of randomly selected fishing events. This review process randomly selects 10% of the events from each trip and enumerates the catch of each species during the entire event. Originally designed as a random check on the veracity of the fisher logs, these review data were used in this study to provide an unbiased estimate of mean catch per event and its variance; mean catch per event was then expanded to total catch by the total number of events. Since these data come from video footage collected at the moment of capture, the video estimate cannot be corrupted by misreporting of discards or by dumping fish after being retained. Thus, the video data provide an unbiased and virtually independent catch estimate—rare in fisheries monitoring—that captures the extent to which the official catch accounting systems might be biased.

Action agencies have encouraged the development of a modified electrical fish barrier system to deter upstream movements of California sea lions Zalophus californianus as a means to reduce their predation on returning adult Pacific salmon Oncorhynchus spp. within rivers along the West Coast of North America. Given that the barrier system does not discriminate which species will experience electrical shock, we studied the potential effects of the sea lion barrier on the survival, behavior, physiology, and injury of white sturgeon Acipenser transmontanus. Fish subjected to acute electroshock had high survival (100%). Conversely, fish that became entrained within the electric field and therefore experienced chronic electroshock had lower survival (93%). White sturgeon altered their behavior by spending significantly more time avoiding the area over the barrier when electrical power was applied as compared with controls. Fish that experienced acute electroshock spent more time remaining motionless, presumably recovering from physiological disturbance. Our results indicate that white sturgeon had significantly higher plasma lactate than controls and that lactate remained at elevated levels for at least 4 h after electroshock. Plasma glucose, ion concentrations (chloride, sodium, and potassium), and indicators of cell damage (plasma hemoglobin and enzyme activity of aspartate transaminase) did not differ between electroshocked fish and controls. We did not observe any notable hemorrhages or notochord injuries in white sturgeon that experienced electrical shock. Our results suggest that the location for the electrical barrier system should be rigorously examined before barrier deployment and that the dates, frequency, and duration of use should be further refined to ensure that negative effects on nontarget species such as white sturgeon are minimized.

The data-poor status of a fishery usually occurs because the fishery is low in value and as such has the lowest priority for funding. However, there is often no formal evaluation of the cost of data collection versus the benefits it brings. In this article, we describe how the costs and benefits of data collection can be evaluated within the context of fisheries management procedures. Based on a data-poor fishery in New Zealand, we illustrate how to evaluate the utility associated with simple management procedures that incorporate no monitoring, fixed monitoring, or adaptive monitoring. We demonstrate that it is feasible to do formal evaluations of alternative data collection regimes by including their costs in a utility function that incorporates other performance measures. Our particular example demonstrates the potential benefits of monitoring even in low-value fisheries and shows, in principle, the gains that can be made through the use of management procedures that include adaptive monitoring.

We contrast two paradigms for fisheries management decision making: the “assessment” paradigm, which is based around stock assessments, and the “procedural” paradigm, which is based around management procedures. The assessment paradigm has difficulty in providing management for data-poor stocks, and we illustrate this in the New Zealand context. In contrast, the procedural paradigm has the potential to be useful for the data-poor stocks. However, to date, it has not served data-poor fisheries well because most of the development of management procedures has been for high-value, data-rich stocks. This may be because several aspects of the procedural paradigm are misunderstood or neglected. Giving appropriate attention to these aspects will improve the application of fisheries management procedures, particularly for data-poor stocks. For example, more attention needs to be given to the method for presenting evaluation results to decision makers in ways that more easily allow them to make trade-offs among multiple management objectives. We also argue that the design, evaluation, and selection of management procedures should be treated as an exercise in engineering, particularly by applying generic solutions to data-poor cases for which specific solutions are usually not readily developed.