The primary objective of the Shrimp Resource Assessment is to provide scientific information and alternative resource use strategies for the management of the regional pink shrimp fishery resource. To accomplish this objective, five specific annual tasks were developed: 1) Collect and code shrimp fishery logbook data, match logbook information to...
Rebuilding of some U.S. West Coast rockfish (Sebastes spp.) stocks relies heavily on mandatory fishery discard, however the long-term condition of discarded fish experiencing capture-related barotrauma is unknown. We conducted two studies designed to evaluate delayed mortality, physical condition,and behavioral competency of yelloweye rockfish, Sebastes ruberrimus, experiencing barotrauma during capture...
Temperate nearshore reefs along the Pacific coast of North America are highly valuable to commercial and recreational fisheries yet comprise a small fraction of the seabed. Monitoring fisheries resources in this region is difficult; high-relief structural complexity and adverse sea conditions have led to a paucity of information on temperate...
We evaluated the external signs of barotrauma and 48-h post-recompression survival for 17 54 canary and 81 yelloweye rockfish captured at depths of 46-174 m, much deeper than a 18 similar prior experiment, but within the depth range of recreational fishery catch and 19 discard. Survival was measured using specialized...
We evaluated how the use of bait as a fish attractant influenced the species and size composition 20 of demersal fishes viewed with a stereo video lander, at 160 sampling sites at Stonewall Bank, a 21 deepwater rocky reef complex in Oregon waters. We also studied the effectiveness of stereo...
Oregon ocean shrimp annual harvest relies on the successful recruitment and growth of age one shrimp. Changes in oceanic conditions appear to have major impacts on recruitment, spatial abundance and growth rates. Successful recruitment has been identified with the timing and strength of the spring transition generating oceanic conditions favorable...
Long-term data sets that quantitatively confirm basic ecological theory are rare for field
populations. Highly variable recruitment often causes wide temporal variation in population
age distribution and basic theory for adaptive sex ratio often predicts ‘sex ratio tracking’ to
match the fluctuating age distribution. Using sex-changing shrimp as a model...
We describe the development and practical field testing of a rugged, unbaited video lander as a visual survey tool for fishes inhabiting structurally complex, high-relief, deepwater rocky reefs. Our autonomous, high-resolution, low-light, color video lander system utilized a smooth frame design that incorporated a series of breakaway attachments and inexpensive...
We hypothesized that bycatch may affect the quality of the shrimp by causing breakage. A double-rigged commercial shrimp vessel was chartered for test fishing. One net employed a Nordmore grate BRD and the other served as a control. Bycatch was measured from each net.
The shrimp catch was kept separate...
We used acoustic telemetry techniques to study the movements of eight species of Pacific rockfish (genus Sebastes) inhabiting Siletz Reef, a high-relief rocky reef complex on the Oregon coast. Our primary interest was evaluating potential residence times for rockfish species in small, no-take marine protected areas (MPAs) like those recently...
We evaluated the effect of barotrauma on the behavior of nine species of Pacific rockfish Sebastes spp. after hook-and-line capture and release using a video-equipped underwater release cage. Sampling was conducted across a range of bottom depths (12-194 m), mostly where barotrauma resulting from an expanded swim bladder and gaseous...
Changes in the spatial distribution of U.S. west coast bottom-trawl effort in relation
to areas of prime habitat for rockfish Sebastes spp. were evaluated between 1992 and 2001. Prime trawlable rockfish habitat (PTRH) was defined based on the spatial distribution of high rockfish catches from logbook data for 1992–1995. Bottom-trawl...
Fishes with closed swim bladders regulate buoyancy during depth changes by secreting and
resorbing swim bladder gases. Forced ascent during fishery capture results in barotrauma caused by rapid expansion and exsolution of gases from body fluids. Pressure changes in hyperbaric chambers were used to examine changes in swim bladder integrity...
The lingcod Ophiodon elongatus is a benthic marine fish commonly caught by groundfish trawlers and discarded due to low catch limits. Managers must account for the mortality of bycatch to assess population status accurately. Our objectives were to estimate the actual mortality of trawl-discarded lingcod (50- 84 cm) and describe...
We evaluated the effect of capture depth and fish size on the ability of several Pacific rockfishes Sebastes spp. to resubmerge after hook-and-line capture and surface release. We observed fish as they were released into a bottomless floating enclosure, and we recorded submergence success within a 5-min time limit. Submergence...
We tested the potential of a selective flatfish trawl to reduce bycatch of slope rockfish in the upper continental slope bottom-trawl fishery (250–500 m) on the U.S. West Coast. The trawl we tested differed from typical slope trawls in that it was a low-rise, two-seam trawl with a severely cut...