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 Western Pacific Fishery Information Network: A Fisheries Information System

The Western Pacific Fishery Information Network (WPACFlN) is an intergovernmental agency cooperative program sponsored by the National Marine Fisheries Service (NMFS) to help participating island fisheries agencies carry out data collection, analysis, reporting programs, and data management activities to better support fisheries management under the Magnuson Fishery Conservation and Management Act; and to help meet local fisheries information and management needs. The WPACFlN is the central source of information for Federal fisheries management of most fisheries in American Samoa, Guam, and the Northern Mariana Islands, and it plays an important role in acquiring fisheries data in Hawaii. This paper describes the development and status of this fishery information system.

On the Distribution and Fishery Potential of the Japanese Red Crab Chaceon granulatus in the Palauan Archipelago, Western Caroline Islands

A deep-water trapping survey in the Palauan archipelago, Western Caroline Islands, has revealed an abundance of the Japanese red crab, Chaceon granulatus. The recorded depth range (250-900 m) is similar to that of other geryonids, but the large numbers of females caught below 700 m is atypical. Mean yields in excess of 5 kg crabs plus 1 kg shrimp, Heterocarpus laevigatus, by-catch per trap-night were attainable at optimum depths. Chaceon granulatus is apparently a very large geryonid, with maximum weights of 2.02 kg and 1.51 kg recorded for male and female specimens, respectively. A range of body colors was observed: Orange-red shades appear to dominate the deeper waters (below 500 m) while yellow-tan colors are more abundant in the upper reaches. Preliminary evidence suggests that Chaceon granulatus is highly marketable, and the infrastructure in Palau is such that crabs could either be marketed fresh locally or airfreighted to Japan as a quick-frozen product. The high post-trapping survival rates observed indicate that maintaining crabs in live-holding tanks may be a feasible option. The large catches and quality of deep-water crabs taken suggests that the Palauan population of Chaceon granulatus may be able to support a small-scale fishery. It is not yet known whether this population is unusually large or whether these findings typify the deep forereef fauna of the region.

Blue Marlin, Makaira nigricans, Movements in the Western North Atlantic Ocean: Results of a Cooperative Game Fish Tagging Program, 1954-88

Blue marlin, Makaira nigricans, tag and recapture data are summarized for 1954-1988. During this period, 8,447 fish have been tagged and only 30 (0.35 percent) have been returned. Results of the tagging program indicate that blue marlin not only travel considerable distances (7,OOO km from the U. S. Virgin Islands to the Ivory Coast of West Africa), but have remained at large for up to 8 years. Seasonal movements, however, are difficult to determine accurately.

Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall)

ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than on steeply sloping island shores. Phyllospadix abundance was positively correlated with P. interruptus abundance; however, at Santa Catalina Island, the Phyllospadix habitat was not extensive enough to be the sole lobster nursery. In laboratory tests, puerulus larvae and early juveniles chose Phyllospadix over rubble rocks or broad-bladed kelp, but did not consistently prefer Phyllospadix over reticulate algae. Ecology, growth, and behavior of juvenile P. interruptus inhabiting a discrete Phyllospadix habitat at Bird Rock, Santa Catalina Island, were investigated from October 1974 through December 1976 by means of frequent scuba surveys. Pueruli settled from June to November. Peak recruitment occurred from July to September, when seasonal temperatures were maximal. Settled larvae were approximately one year old. Juvenile growth was determined by size-frequency, single molt increment, mark-recapture, and laboratory culture studies. Carapace length vs. wet weight relationships fit standard power curve equations. Bird Rock juveniles grew from 7 to 32mm CL in 10-11 molts and from 32 to 56mm CL in 5-6 molts during their first and second benthic years, respectively. Growth rates were similar for males and females. Juveniles regenerating more than two limbs grew less per molt than intact lobsters. Long-term growth of laboratory-reared juveniles was 20% less than that of field lobsters. Growth component multiple regression analyses demonstrated that molt increment was directly proportional to premolt size and temperature for age 1+ lobsters. Molt frequency was inversely proportional to size and directly proportional to temperature. Temperature affected age 2+ lobsters similarly, but molt increment was independent of size, and molt frequency declined at a different rate. Juvenile growth rates more than doubled during warm water months compared to cold water months, primarily because of increased molt frequency. Based on results from this study and from previous investigations, it is estimated that P. interruptus males and females become sexually mature by ages 4 and 5 years, respectively, and that legai size is reached by 7 or 8 years of age. Juvenile P. interruptus activity patterns and foraging behavior were similar to those of adults, except that juvenile home ranges were proportionally smaller, and small juveniles were apparently not attracted to distant food. Small mollusks, abundant in Phyllospadix habitats, were the major food items. Size-dependent predation by fish and octopus apparently caused the considerable juvenile mortality observed at Bird Rock. Juveniles approaching 2 years of age gathered in mixed size-class aggregations by day and foraged beyond the grass beds at night. In autumn, these juveniles migrated to deeper habitats, coincident with new puerulus settlement in the Phyllospadix beds. Based on strong inferences from the results, it is proposed that size-dependent predation is the most important factor determining the !ife history strategy of juvenile P. interruptus. Life history tactics promoting rapid growth apparently function dually in reducing the period of high vulnerability to predation and decreasing the time required to reach sexual maturity. The Phyllospadix habitat is an excellent lobster nursery because it provides shelter from predators and possesses abundant food resources for sustaining optimum juvenile growth rates in shallow, warm water.