A History of the Pearl Oyster Fishery in the Archipielago de las Perlas, Panama

The pearl oyster, Pinctada margaritifera mazatlanica, was once found around the Archipielago de las Perlas in Panama in abundance and it supported a substantial fishery by hard hat divers. The products were pearls, shells used for making buttons, and meats used locally for food. After the mid 1920’s, the fishery declined due to overfishing, and by the 1940’s it was nearly gone. The oysters began to repopulate the grounds during the 1970’s, but the oysters remain relatively scarce. Fishing has since resumed on a small scale by skin divers using face masks.

Biological Characteristics and Fishery Assessment of Alaska Plaice, Pleuronectes quadrituberculatus, in the Eastern Bering Sea

Alaska plaice, Pleuronectes quadrituberculatus, is one of the major flatfishes in the eastern Bering Sea ecosystem and is most highly concentrated in the shallow continental shelf of the eastern Bering Sea. Annual commercial catches have ranged from less than 1,000 metric tons (t) in 1963 to 62,000 t in 1988. Alaska plaice is a relatively large flatfish averaging about 32 cm in length and 390 g in weight in commercial catches. They are distributed from nearshore waters to a depth of about 100 m in the eastern Bering Sea during summer, but move to deeper continental shelf waters in winter to escape sea ice and cold water temperatures. Being a long-lived species (>30 years), they have a relatively low natural mortality rate estimated at 0.20. Maturing at about age 7, Alaska plaice spawn from April through June on hard sandy substrates of the shelf region, primarily around the 100 m isobath. Prey items primarily include polychaetes and other marine worms. In comparison with other flatfish, Alaska plaice and rock sole, Pleuronectes bilineatus, have similar diets but different habitat preferences with separate areas of peak population density which may minimize interspecific competition. Yellowfin sole, Pleuronectes asper, while sharing similar habitat, differs from these two species because of the variety of prey items in its diet. Competition for food resources among the three species appears to be low. The resource has experienced light exploitation since 1963 and is currently in good condition. Based on the results of demersal trawl surveys and age-structured analyses, the exploitable biomass increased from 1971 through the mid-1980’s before decreasing to the 1997 level of 500,000 t. The recommended 1998 harvest level, Allowable Biological Catch, was calculated from the Baranov catch equation based on the FMSY harvest level and the projected 1997 biomass, resulting in a commercial harvest of 69,000 t, or about 16% of the estimated exploitable biomass.

Review of a Small-scale Pelagic Longline Fishery off Northeastern Brazil

The annual catches of four small longliners operating off northeast Brazil from 1983 to 1997 were examined across different areas and locations. The total catch comprised tunas (30%), sharks (54%), billfishes (12%), and other fish species (4%). Fishing strategy and annual composition of catches showed large spatial and temporal variabilities with the dominant catches alternating among yellowfin tuna, Thunnus albacares; gray sharks, Carcharhinus spp.; and blue shark, Prionace glauca. Catches of blue and gray sharks showed a significant interaction among seamounts, with gray sharks occurring in maximum abundance around those seamounts that had relatively deep summits and low-sloping depth profiles. Results are discussed in terms of the various factors that may have influenced distribution of effort.

Declining Rockfish Lengths in the Monterey Bay, California, Recreational Fishery, 1959–94

California’s Monterey Bay area is an important center of recreational fishing for rockfish of various Sebastes species. The species composition of commercial passenger fishing vessel catches from 1959 to 1994 varied with changes in fishing location and depth. The shift from shallow nearshore locations to deeper offshore locations in the late 1970’s and 1980’s changed the emphasis from the blue rockfish, S. mystinus, of shallow waters to the deeper, commercially fished chilipepper, S. goodei, and bocaccio, S. paucispinis. The mean size of rockfish in the catch increased as the latter species were targeted at greater depths but then declined as stocks of older fish disappeared by the mid 1980’s. During 1960–94 the mean size of all ten leading species in the recreational catch declined. The declines ranged from 1% for canary rockfish, S. pinniger, to 27% for chilipepper. The sizes of the deeper living species declined more than those of shallower species. The low frequency of strong recruitment events and increase in fishing mortality and natural mortality appear to have contributed to the declining mean size. The scarcity of older fish, observed as a drop in mean size to below the size of maturity for 50% of females, leads to concern for future recruitment of the larger species, especially bocaccio, chilipepper, yellowtail rockfish, S. flavidus, and canary rockfish.

The Origin of the Florida Sponge Fishery

Sponges were used domestically by Key West, Fla., pioneers soon after the town was settled in 1822 (Collins, 1887). Fortunately, aroung 1852, it was discovered that Florida sponges were able to compete with imported sponges from the Mediterranean, and they soon became commercially successful (Moore, 1910). These Florida-caught sponges were shipped to markets in New York and sold for domestic cleaning and personal hygiene, as upholstery stuffing and packing material, and for cleaning military cannons.

An Assessment of Fishery Yields from the East China Sea Ecosystem

A first assessment ofimportant East China Sea fisheries was carried out using data from 1956 to 1993. Two different data sets were available: 1) catch and effort data taken from landings and boat registrations and 2) catch and effort data from skipper's logs taken at sea. The two sets provided similar trends in CPUE over the study period. Stocks of high value, low volume species have been fished heavily and now produce very low landings or have been depleted (e.g. small and large yellow croaker). Some high volume and low value species have also been heavily fished (e.g. green filefish) while others (e.g. hairtail) are still producing high landings. Surplus production models were fitted to seven stocks. All showed considerable fluctuations in landings around MSY. The green filefish stock had an estimated MSY of around 160,000 tlyr at an effort of 2,500,000 kw and was depleted by a combination of excessive effort (around 4,000,000 kw in 1993) and marked fluctuations in landings (up to 70,000 tlyr above or below MSY). A sustainable policyfor managing ECS fisheries should address the effects ofboth effort and environmental variation.

The 1996 U.S. Purse Seine Fishery for Tropical Tunas in the Central-Western Pacific Ocean

The U.S. tropical tuna purse seine fleet has fished the central-western Pacific Ocean under the South Pacific Tuna Treaty since 1988. The 1996 fishery was the poorest since the start ofthe Treaty. Fishing effort declined due to the financial collapse of a large fishing enterprise. Catches reached record lows for yellowfin tuna, Thunnus albacares, and skipjack tuna, Katsuwonus pelamis, and continued a declining trend that started in 1995. Catch rates also decreased to the lowest levels since 1991. Whether this declining trend in catch rates is due to reduced availability of fish caused by cyclic ocean environmental changes affecting vulnerability or to reduced abundance from excessive fishing pressure is not yet known and needs to be assessed.

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.

Catch and Bycatch in the Shark Drift Gillnet Fishery off Georgia and East Florida

An observer program of the shark drift gillnet fishery off the Atlantic coast of Florida and Georgia was begun in 1993 to define the fishery and estimate bycatch including bottlenose dolphin, Tursiops truncatus, and sea turtles. Boats in the fishery were 12.2-19.8 m long. Nets used were 275-1,800 m long and 3.2-4.1 m deep. Stretched-mesh sizes used were 12.7-29.9 cm. Fishing trips were usually <18 h and occurred within 30 n.mi. of port. Fishing with an observer aboard occurred between Savannah, Ga., and Jacksonville, Fla., and off Cape Canaveral, Fla. Nets were set at least 3 n.mi. offshore. Numbers of boats in the fishery increased from 5 in 1993 to 11 in 1995, but total trips decreased from 185 in 1994 to 149 in 1995. During 1993-95, 48 observer trips were completed and 52 net sets were observed. No marine mammals were caught and two loggerhead turtles, Caretta caretta, were caught and released alive. A total of 9,270 animals (12 shark, 21 teleost, 4 ray, and 1 sea turtle species) were captured. Blacknose, Carcharhinus acronotus; Atlantic sharpnose, Rhizoprionodon terraenovae; and blacktip shark, C. limbatus), were the dominant sharks caught. King mackerel, Scomberomorus cavalIa; little tunny, Euthynnus alleteratus; and cownose ray, Rhinoptera bonasus, were the dominant bycatch species. About 8.4% of the total catch was bycatch. Of the totals, 9.4% of the sharks and 37.3% ofthe bycatch were discarded.

Recent Trends in the Catch of Undersized Swordfish by the U.S. Pelagic Longline Fishery

U.S. commercial vessels fishing in the Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico have been subject to regulations limiting the landing of swordfish less than 25 kg whole weight since June 1991. The intent of those regulations was to reduce the mortality of immature swordfihs. Plots of fishing effort from 1990 to 1994 indicate that the regulations were effective in some areas. Fishing effort decreased after 1991 in the Venezuelan Basin, a swordfish nursery area. However, in areas close to the U.S. coastline, effort did not appear to shift away from areas where immature swordfish were discarded. To identify areas with high rates of discarding, plots were made showing areas where the number of discarded swordfish was equal to or greater than the number of fish landed.

Charles H. Gilbert, Pioneer Ichthyologist and Fishery Biologist

Charles Henry Gilbert (Fig. 1) was a pioneer ichthyologist and, later, fishery biologist of particular significance to natural history of the western United States. Born in Rockford, Illinois on 5 December 1859, he spent his early years in Indianapolis, Indiana, where, in 1874, he came under the influence of his high school teacher, David Starr Jordan (1851-1931). Gilbert graduated from high school in 1875, and when Jordan became a professor of natural history at Butler University in Irvington, Indiana, Gilbert followed, and received his B.A. degree in 1879. Jordan moved to Indiana University, in Bloomington, in the fall of 1879, and Gilbert again followed, earning his M.S. degree in 1882 and his Ph.D. in 1883 in zoology. His doctorate was the first ever awarded by Indiana University.

Florida's Halfbeak, Hemiramphus spp., Bait Fishery

Two species of halfbeaks, ballyhoo, Hemiramphus brasiliensis, and balao, H. balao, form the basis of a relatively small but valuable bait fishery in southeastern Florida. Halfbeak landings increased rapidly in the late 1960's but are now relatively stable (about 450,000 kg or 1 million lb annually), and their ex-vessel price is about $600,000. Fishing methods, which had changed in the late 1960's when landings increased, have changed little since the 1970's. Data from a fishery-dependent survey (1988-91) show that catch rates were highest from October to February, when catches were dominated by large ballyhoo (>200 mm or 8 inches fork length (FL)); rates were lowest from May to September, when catches contained both species in more equal numbers and the size range was greater (about 150-250 mm FL) than it was for winter landings. There was little bycatch, and only flyingfishes (Exocoetidae) and needlefishes (Belonidae) occurred consistently. Comparisons of the 1988-91 data with similar data reported from 1974 indicated that halfbeak populations have remained relatively stable.

Australian Vessel Performance in the East Coast Tuna Longline Fishery

A sample of daily observations on the activities of Australian vessels longlining for yellowfin tuna, Thunnus albacares, during 1987-90 was analyzed, using a production junction approach, to determine the effects of vessel characteristics and operational practices and conditions. Significant differences were found between the tuna fisheries in the northern and southern regions of the inshore yellowfin tuna fishery in the east Australian Exclusive Economic Zone. The type of vessel used, and fishing practices such as soaktime, patrolling the longline, and choice of surface water temperature were found to have significant effects on yellowfin tuna catch rates.

Biology and Fishery for Atlantic Thread Herring, Opisthonema oglinum, along the North Carolina Coast

Thread herrings, Opisthonema spp., are small, nearshore, pelagic clupeid fishes that form dense, surface schools in tropical to subtropical coastal waters. Ecologically, thread herrings form an important forage base for many large, predatory fishes (Finucane and Vaught, 1986). Commercially, thread herrings are targeted by artisanal to moderate-sized seine fisheries off the coasts of Ecuador and Peru (Patterson and Santos, 1992), Costa Rica (Stevenson and Carranza, 1981), Venezuela, the continental margins of the Caribbean, the Gulf of Mexico, and near the islands of Cuba, Hispaniola, Puerto Rico, Jamaica, and Trinidad (Reintjes, 1978). Most of the catch is reduced to fish meal and fish oil (Patterson and Santos, 1992), although minor quantities are used for human consumption (Reintjes, 1978).

Observations of the 1992 U.S. Pelagic Pair Trawl Fishery in the Northwest Atlantic

Pelagic pair trawling for tuna, Thunnus spp., and swordfish, Xiphias gladius, was introduced in U.S. Northwest Atlantic waters in 1991. During autumn (October-November) of 1992 under the authority oft he Federal Atlantic Swordfish Regulations, the National Marine Fisheries Service placed observers aboard pelagic pair trawl vessels to document the catch, bycatch, discard, and gear used in this new fishery. The fishery is conducted primarily at night along shelf-edge waters from June to November. In late 1991, revised regulations restricted swordfish to bycatch in this fishery resulting in pelagic pair trawl vessels targeting tuna throughout 1992. Analyses of 1992 data indicate that albacore, T. alalunga, was the predominant species caught, although yellowfin tuna, T. albaeares, and bigeye tuna, T. obesus, were the preferred target species. Bycatch also included swordfish, large sharks, pelagic rays and other pelagic fishes, other tunas, and marine mammals.