Development, use and management of the Zhoushan fishing ground, China

The Zhoushan fishing area contains the Zhoushan archipelagos, whose population is nearly 1 million, including over 300,000 fishermen. A detailed account is given of the environment and its resources; there are more than 300 species of fish, over 60 species of shrimp, more than 10 species of crab and more than 50 species of algae in the area. The history of fishery development in the area is described, outlining motorization, technology, and education. Various regulations and management activities, implemented in the 1980s, are highlighted.

Sex-change rules, stock dynamics, and the performance of spawning-per-recruit measures in protogynous stocks

Predicting and under-standing the dynamics of a population requires knowledge of vital rates such as survival, growth, and reproduction. However, these variables are influenced by individual behavior, and when managing exploited populations, it is now generally realized that knowledge of a species’ behavior and life history strategies is required. However, predicting and understanding a response to novel conditions—such as increased fishing-induced mortality, changes in environmental conditions, or specific management strategies—also require knowing the endogenous or exogenous cues that induce phenotypic changes and knowing whether these behaviors and life history patterns are plastic. Although a wide variety of patterns of sex change have been observed in the wild, it is not known how the specific sex-change rule and cues that induce sex change affect stock dynamics. Using an individual based model, we examined the effect of the sex-change rule on the predicted stock dynamics, the effect of mating group size, and the performance of traditional spawning-per-recruit (SPR) measures in a protogynous stock. We considered four different patterns of sex change in which the probability of sex change is determined by 1) the absolute size of the individual, 2) the relative length of individuals at the mating site, 3) the frequency of smaller individuals at the mating site, and 4) expected reproductive success. All four pat-terns of sex change have distinct stock dynamics. Although each sex-change rule leads to the prediction that the stock will be sensitive to the size-selective fishing pattern and may crash if too many reproductive size classes are fished, the performance of traditional spawning-per-recruit measures, the fishing pattern that leads to the greatest yield, and the effect of mating group size all differ distinctly for the four sex-change rules. These results indicate that the management of individual species requires knowledge of whether sex change occurs, as well as an understanding of the endogenous or exogenous cues that induce sex change.

Indirect validation of the age-reading method for Pacific cod (Gadus macrocephalus) using otoliths from marked and recaptured fish

Two examples of indirect validation are described for age-reading methods of Pacific cod (Gadus macrocephalus). Aging criteria that exclude faint translucent zones (checks) in counts of annuli and criteria that include faint zones were both tested. Otoliths from marked and recaptured fish were used to back-calculate the length of each fish at the time of its release by using measurements of the area of annuli. Estimated fish size at time of release and actual observed fish size were similar, supporting the assumption that translucent zones are laid down on an annual basis. A second method for validating reading criteria used otolith age and von Bertalanffy parameters, estimated from the tagging data, to predict how much each fish grew in length after tagging. We found that otolith aging criteria applied to otoliths from tagged and recovered Pacific cod predicted quite accurately the growth increments that we observed in these specimens. These results provide further evidence that the current aging criteria are not underestimating the age of the fish and support our current interpretation of checks (i.e., as subannual marks). We expect these indirect validations to advance age determination for Pacific cod, which in turn would enhance development of stock assessment methods based on age structure for this species in the eastern Bering Sea.

Descriptions of the U.S. Gulf of Mexico Reef Fish Bottom Longline and Vertical Line Fisheries Based on Observer Data

In July 2006, a mandatory observer program was implemented to characterize the commercial reef fish fishery operating in the U.S. Gulf of Mexico. The primary gear types assessed included bottom longline and vertical line (bandit and handline). A total of 73,205 fish (183 taxa) were observed in the longline fishery. Most (66%) were red grouper, Epinephelus morio, and yellowedge grouper, E. flavolimbatus. In the vertical line fishery, 89,015 fish (178 taxa) were observed of which most (60%) were red snapper, Lutjanus campechanus, and vermilion snapper, Rhomboplites aurorubens. Based on surface observations of discarded under-sized target and unwanted species, the majority of fish were released alive; minimum assumed mortality was 23% for the vertical line and 24% for the bottom longline fishery. Of the individuals released alive in the longline fishery, 42% had visual signs of barotrauma stress (air bladder expansion/and or eyes protruding). In the vertical line fishery, 35% of the fish were released in a stressed state. Red grouper and red snapper size composition by depth and gear type were determined. Catch-per-unit-effort for dominant species in both fisheries, illustrated spatial differences in distribution between the eastern and western Gulf. Hot Spot Analyses for red grouper and red snapper identified areas with significant clustering of high or low CPUE values.

Classification of Coastal Communities Reporting Commercial Fish Landings in the U.S. Northeast Region: Developing and Testing a Methodology

The National Marine Fisheries Service is required by law to conduct social impact assessments of communities impacted by fishery management plans. To facilitate this process, we developed a technique for grouping communities based on common sociocultural attributes. Multivariate data reduction techniques (e.g. principal component analyses, cluster analyses) were used to classify Northeast U.S. fishing communities based on census and fisheries data. The comparisons indicate that the clusters represent real groupings that can be verified with the profiles. We then selected communities representative of different values on these multivariate dimensions for in-depth analysis. The derived clusters are then compared based on more detailed data from fishing community profiles. Ground-truthing (e.g. visiting the communities and collecting primary information) a sample of communities from three clusters (two overlapping geographically) indicates that the more remote techniques are sufficient for typing the communities for further in-depth analyses. The in-depth analyses provide additional important information which we contend is representative of all communities within the cluster.

Transboundary Movement of Atlantic Istiophorid Billfishes Among International and U.S. Domestic Management Areas Inferred from Mark-Recapture Studies

Billfish movements relative to the International Commission for the Conservation of Atlantic Tunas management areas, as well as U.S. domestic data collection areas within the western North Atlantic basin, were investigated with mark-recapture data from 769 blue marlin, Makaira nigricans, 961 white marlin, Tetrapturus albidus, and 1,801 sailfish, Istiophorus platypterus. Linear displacement between release and recapture locations ranged from zero (all species) to 15,744 km (mean 575, median 119, SE 44) for blue marlin, 6,523 km (mean 719, median 216, SE 33) for white marlin, and 3,845 km (mean 294, median 98, SE 13) for sailfish. In total, 2,824 (80.0%) billfish were recaptured in the same management area of release. Days at liberty ranged from zero (all species) to 4,591 (mean 619, median 409, SE 24) for blue marlin, 5,488 (mean 692, median 448, SE 22) for white marlin, and 6,568 (mean 404, median 320, SE 11) for sailfish. The proportions (per species) of visits were highest in the Caribbean area for blue marlin and white marlin, and the Florida East Coast area for sailfish. Blue marlin and sailfish were nearly identical when comparing the percent of individuals vs. the number of areas visited. Overall, white marlin visited more areas than either blue marlin or sailfish. Seasonality was evident for all species, with overall results generally reflecting the efforts of the catch and release recreational fishing sector, particularly in the western North Atlantic. This information may be practical in reducing the uncertainties in billfish stock assessments and may offer valuable insight into management consideration of time-area closure regulations to reduce bycatch mortality of Atlantic billfishes.

Removal of Sea Lettuce, Ulva spp., in Estuaries to Improve the Environments for Invertebrates, Fish, Wading Birds, and Eelgrass, Zostera marina

Mats (biomasses) of macroalgae, i.e. Ulva spp., Enteromorpha spp., Graciolaria spp., and Cladophora spp., have increased markedly over the past 50 years, and they cover much larger areas than they once did in many estuaries of the world. The increases are due to large inputs of pollutants, mainly nitrates. During the warm months, the mats lie loosely on shallow sand and mud flats mostly along shorelines. Ulva lactuca overwinters as buds attached to shells and stones, and in the spring it grows as thalli (leaf fronds). Mats eventually form that are several thalli thick. Few macroinvertebrates grow on the upper surfaces of their thalli due to toxins they produce, and few can survive beneath them. The fish, crabs, and wading birds that once used the flats to feed on the macroinvertebrates are denied these feeding grounds. The mats also grow over and kill mollusks and eelgrass, Zostera marina. An experiment was undertaken which showed that two removals of U. lactuca in a summer from a shallow flat in an estuarine cove maintained the bottom almost free of it.

Precious Corals in Hawaii: Discovery of a New Bed and Revised Management Measures for Existing Beds

The fishery for deepwater precious corals in the Hawaiian Islands has experienced an on-and-off history for almost 40 years. In spite of this, research, driven primarily by the precious coral jewelry industry, remains active. In this paper, the results of deepwater surveys in 2000 and 2001 are reported. In summary, a new bed on the summit of Cross Seamount is described and revised estimates of MSY’s for pink coral, Corallium secundum; red coral, Corallium regale; and gold coral, Ger ardia sp., in the two known beds off Makapuu, Oahu, and Keahole Point, Hawaii, in the main Hawaiian Islands, are presented. The population dynamics of each species is described, as well as their ecological limits on Hawaii’s deep reefs, island shelves, and seamounts. The local supply of precious coral in the main Hawaiian Islands is sufficient to support the local industry, but cost/ benefits of selective harvest requirements and weather constraints limit profitability of the fish

A Brief Interpretation of Summer Flounder, Paralichthys dentatus, Movements and Stock Structure with New Tagging Data on Juveniles

Summer flounder, Paralichthys dentatus, are managed as a single stock along the Atlantic coast from the U.S.– Canada border to the southern border of North Carolina. Justification of the single-stock approach is based on lack of genetic evidence for multiple stocks and the difficulty presented by managing the species from Cape Hatteras to the U.S.–Canada border. In this review, we present an interpretation of various morphometric, meristic, biochemical, and tagging studies, published and unpublished, that indicate the presence of two, or possibly three, distinct stocks in the management area. In addition, we have included new data from a tagging study that was conducted on juveniles from Virginia that aids in defining the stock(s) north of Cape Hatteras. Summer flounder, overfished for the past two decades, is recovering, and reconsideration of proposed stock structure could have direct implications for management policy decisions.

Trends and Potential Interactions Between Pinnipeds and Fisheries of New England and the U.S. West Coast

Long-term trends in the abundance and distribution of several pinniped species and commercially important fisheries of New England and the contiguous U.S. west coast are reviewed, and their actual and potential interactions discussed. Emphasis is on biological interactions or competition. The pinnipeds include the western North Atlantic stock of harbor seals, Phoca vitulina concolor; western North Atlantic gray seals, Halochoerus grypus; the U.S. stock of California sea lions, Zalophus californianus californianus; the eastern stock of Steller sea lions, Eumetopias jubatus; and Pacific harbor seals, Phoca vitulina richardii. Fisheries included are those for Atlantic cod, Gadus morhua; silver hake, Merluccius bilinearis; Atlantic herring, Clupea harengus; the coastal stock of Pacific whiting, Merluccius productus; market squid, Loligo opalescens; northern anchovy, Engraulis mordax; Pacific her-ring, Clupea pallasi; and Pacific sardine, Sardinops sagax. Most of these pinniped populations have grown exponentially since passage of the U.S. Marine Mammal Protection Act in 1972. They exploit a broad prey assemblage that includes several commercially valuable species. Direct competition with fisheries is therefore possible, as is competition for the prey of commercially valuable fish. The expanding pinniped populations, fluctuations in commercial fish biomass, and level of exploitation by the fisheries may affect this potential for competition. Concerns over pinnipeds impacting fisheries (especially those with localized spawning stocks or at low biomass levels) are more prevalent than concerns over fisheries’ impacts on pinnipeds. This review provides a framework to further evaluate potential biological interactions between these pinniped populations and the commercial fisheries with which they occur.

The California Red Sea Urchin, Strongylocentrotus franciscanus, Fishery: Catch, Effort, and Management Trends

California's red sea urchin, Strongylocentrotus franciscanus, catch peaked at 23,577 metric tons (t) in 1988. Since then, catches and CPUE have trended downward at different rates in northern and southern California, with 10,086 t landed statewide in 1995. West coast sea urchin catches and CPUE from British Columbia, Can., to Baja California, Mex., have generally declined during this period which followed a decade of rapid fishery expansion. This expansion was in response to increasing demand from Japan fueled by rising prices based largely on a more favorable export currency exchange rate. West coast stock assessment methods have been based on integrating a combination of fisheries dependent data and population surveys into models at various levels of complexity. California management policy has centered on technical measures such as size limits and seasonal closures and has been largely ineffective in stabilizing declining catches.

The Threatened Status of Steller Sea Lions, Eumetopias jubatus, under the Endangered Species Act: Effects on Alaska Groundfish Fisheries Management

In April 1990, the Steller sea lion, Eumetopias jubatus, was listed as threatened under the U.S. Endangered Species Act by emergency action. Competitive interactions with the billion-dollar Alaska commercial groundfish fisheries have been suggested as one of the possible contributing factors to the Steller sea lion population decline. Since the listing, fisheries managers have attempted to address the potential impacts of the groundfish fisheries on Steller sea lion recovery. In this paper, we review pertinent Federal legislation, biological information on the Steller sea lion decline, changes in the Alaska trawl fishery for walleye pollock, Theragra chalcogramma, since the late 1970's, andpossible interactions between fisheries and sea lions. Using three cases, we illustrate how the listing of Steller sea lions has affected Alaska groundfish fisheries through: I) actions taken at the time of listing designed to limit the potential for directhuman-related sea lion mortality, 2) actions addressing spatial and temporal separation of fisheries from sea lions, and 3) introduction of risk-adverse stock assessment methodologies and Steller sea lion conservation considerations directly in the annual quota-setting process. This discussion shows some of the ways that North Pacific groundfish resource managers have begun to explicitly consider the conservation ofmarine mammal and other nontarget species.

A Cooperative Management Solution to a Fishery Commons

A common property resource with open access, such as a fishery, will be used to excess when faced with sufficient demand. This will lead to an excessive amount of effort on the part of the fishery, resulting in a depletion of the stock. This paper discusses the development of a property rights regime for the Atlantic calico scallop, Argopecten gibbus, fishery of Florida. The management solution of the Calico Scallop Conservation Association (CSCA) provides an example of the assignment of property rights to a common property resource without resorting to governmental intervention. In this particular fishery, self-regulation limited early harvesting which would be uneconomic; there may be other fisheries in which self-regulation could be economically efficient and biologically appropriate. While this solution may not be applicable to all common property resources, for those cases which may be similar; the example of the CSCA provides valuable information that may be helpful in establishing a more efficient use of the resource. Some types of government facilitation may also be useful.

Biology and Management of Deepwater Snappers of the Hawaiian Archipelago

Commercial and recreational deepwater (100-400 m) bottom-fishing in Hawaii targets a multispecies group of lutjanid snappers. Relatively little is known about the life history of these species. Research in Hawaii and elsewhere in the tropical Pacific suggests that most of the species are slow growing, long lived, and have a relatively high age at sexual maturity. Stock assessment is difficult because of the multispecies nature of the fishery. However, recent analysis of commercial fishery data indicates that some of the species may currently be overexploited. Research is underway to determine the efficacy of management measures such as minimum-size limit changes or seasonal and spatial fishery closures to maintain optimal spawning biomass.

The Commercial, Subsistence, and Recreational Fisheries of American Samoa

Domestic fisheries in American Samoa landed 587,000 lb of fish and invertebrates in 1991 worth $993,000. Most of the catch (78%) and value (80%) was taken by the shoreline subsistence fishery that occurs on the coral reefs surrounding the islands. Artisanal fisheries for offshore pelagic fishes (primarily skipjack tuna, Katsuwonus pelamis; and yellowfin tuna, Thunnus albacares) and bottomfishes (snappers, emperors, groupers) accounted for 16% and 3%, respectively, of the domestic catch. Recreational tournament catches for pelagic fishes represented the remainder (3%). While sportfishing is becoming increasingly important, other domestic fisheries have declined in recent years. The shoreline subsistence fishery has dropped by about 25% over the past decade owing to socioeconomic factors and possibly overexploitation. Artisanal fisheries have also declined precipitously in recent years owing to hurricane-related damages, attrition of fishermen, and competition with imports. Artisanal fisheries show some potential for growth, but may be constrained by marketing issues, vessel capabilities, and limited stock sizes (for bottomfish) or local availability of high-value (pelagic) fishes. In contrast to the small-scale domestic fisheries, American Samoa is also homeport to a distant-water fleet of large purse seiners and longliners that fish beyond the EEZ and deliver about 160,000-220,000 short tons of tuna per year to local canneries.