Tag Location and Retention in Black Rockfish: Feasibility of Using PIT Tags in a Wild Marine Species

Tag and recovery programs can provide valuable information on population size and exploitation rates in fishes. Passive integrated transponder (PIT) tags are ideal for use in such programs because they provide identification of individual fish and are invisible to anglers, circumventing problems with nonreporting of tags. Our objective was to determine whether PIT tags could be used successfully to tag black rockfish Sebastes melanops. We tested tag placement and tag retention using intramuscularly injected PIT tags (12 x 2.1 mm) in 227 black rockfish (25-47 cm); three tag placement sites located outside of the area normally filleted were evaluated. Tag retention for all tag sites was 100% after 49 weeks; however, two fish retained inoperative tags, which possibly sustained damage during the tagging procedure. The results indicated that the best tagging site is ventral and anterior to the origin of the pectoral fin. At this site, tag retention is excellent, risk of infection is low, tag movement is minimal, and little or no tissue damage results from the tagging procedure.Keywords: tags, Sebastes melanops, transponders, population structureKeywords: tags, Sebastes melanops, transponders, population structur

The divergent effect of capture depth and associated barotrauma on post-recompression survival of canary (Sebastes pinniger) and yelloweye rockfish (S. ruberrimus)

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 sea cages for holding individual fish. 20 The external physical signs associated with extreme expansion and retention of 21 swimbladder gas (pronounced barotrauma), including esophageal eversion, exophthalmia 22 and ocular emphysema, were common for both species at these capture depths and were 23 more frequent than in prior studies conducted at shallower depths. Despite similar 24 frequencies of most external barotrauma signs, 48-h post-recompression survival of the 25 two species diverged markedly as capture depth increased. Survival of yelloweye 26 rockfish was above 80% across all capture depths, while survival of canary rockfish was 27 lower, declining sharply to just 25% at capture depths greater than 135 m. Fish of both 28 species that were alive after 48 h of caging displayed very few of the external signs of 29 pronounced barotrauma and had a high submergence success rate when released at the 30 surface. Logistic regression analysis, using a combined data set from this and an earlier 31 experiment conducted at shallower capture depths, was used to more broadly evaluate 32 factors influencing post-recompression survival. For canary rockfish, depth of capture 33 was negatively related to survival (P0.05). Exophthalmia and ocular emphysema were each 35 negatively associated with survival for canary rockfish (P0.05).Keywords: Discard mortality, Sebastes, Recompression, Barotrauma, Caging system

Discard Mortality of Trawl-Caught Lingcod in Relation to Tow Duration and Time on Deck

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 their physiological stress response to capture. We investigated three major factors of the trawling operation that may influence lingcod survival: tow duration, fish size, and the amount of time fish were on the deck of the vessel. Survival was monitored for 21 d and each surviving animal was then physically and physiologically evaluated. The results showed that regardless of the duration of the tow, lingcod survival was 100% for animals discarded immediately after the cod end was emptied on deck. All lingcod captured during a tow of average commercial duration demonstrated a maximal stress response, measured by plasma cortisol, glucose, and lactate concentrations. As expected, lingcod from an average duration tow showed decreased survival with increased time on deck, though still had 50% survival after 30 min. This study suggests that discard mortality of lingcod is determined mainly by on-deck sorting and can be minimized by releasing fish quickly upon capture. Accurate estimation of mortality rates for lingcod will depend on the documentation of normal fishing behavior and on-deck sorting procedures.Keywords: lethal limits, Ophiodon elongatus, trawling, bycatc

Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

Little is known about intraspecific variation within the deacon rockfish (Sebastes di‐ aconus), a recently described species found in the northeast Pacific Ocean. We in‐ vestigated population structure among fish sampled from two nearshore reefs (Siletz Reef and Seal Rock) and one offshore site (Stonewall Bank) within a 15,000 neutral loci, whether analyzed independently or classified into nearshore and offshore groups. Male and females were readily distinguished using genetic data and 92 outlier loci were as‐ sociated with sex, potentially indicating differential selection between males and fe‐ males. Morphometric results indicated that there was significant secondary sexual dimorphism in otolith shape, but further sampling is required to disentangle potential confounding influence of age. This study is the first step toward understanding in‐ traspecific variation within the deacon rockfish and the potential management impli‐ cations. Since differentiation among the three sample sites was small, we consider the results to be suggestive of a single stock. However, future studies should evalu‐ ate how the stock is affected by differences in sex, age, and gene flow between the nearshore and offshore environments

Green Sturgeon Physical Habitat Use in the Coastal Pacific Ocean

The green sturgeon (Acipenser medirostris) is a highly migratory, oceanic, anadromous species with a complex life history that makes it vulnerable to species-wide threats in both freshwater and at sea. Green sturgeon population declines have preceded legal protection and curtailment of activities in marine environments deemed to increase its extinction risk. Yet, its marine habitat is poorly understood. We built a statistical model to characterize green sturgeon marine habitat using data from a coastal tracking array located along the Siletz Reef near Newport, Oregon, USA that recorded the passage of 37 acoustically tagged green sturgeon. We classified seafloor physical habitat features with high-resolution bathymetric and backscatter data. We then described the distribution of habitat components and their relationship to green sturgeon presence using ordination and subsequently used generalized linear model selection to identify important habitat components. Finally, we summarized depth and temperature recordings from seven green sturgeon present off the Oregon coast that were fitted with pop-off archival geolocation tags. Our analyses indicated that green sturgeon, on average, spent a longer duration in areas with high seafloor complexity, especially where a greater proportion of the substrate consists of boulders. Green sturgeon in marine habitats are primarily found at depths of 20–60 meters and from 9.5–16.0°C. Many sturgeon in this study were likely migrating in a northward direction, moving deeper, and may have been using complex seafloor habitat because it coincides with the distribution of benthic prey taxa or provides refuge from predators. Identifying important green sturgeon marine habitat is an essential step towards accurately defining the conditions that are necessary for its survival and will eventually yield range-wide, spatially explicit predictions of green sturgeon distribution

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001). Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy.Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388.Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16,

Site Fidelity and Movement of Eight Species of Pacific Rockfish at a High-Relief Rocky Reef on the Oregon Coast

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 designated for Oregon waters (337?1,502 ha). We tagged 6 black rockfish S. melanops, 31 canary rockfish S. pinniger, 9 yelloweye rockfish S. ruberrimus, 5 quillback rockfish S. maliger, and 2 copper rockfish S. caurinus, along with single specimens of china rockfish S. nebulosus, vermilion rockfish S. miniatus, and tiger rockfish S. nigrocinctus, and monitored their movements with a large (about 5,200-ha) receiver grid for over a year. Canary rockfish showed low site fidelity and wide-ranging movements that exceeded the scale of our detection grid and a wide range of vertical movements (up to 27 m). Quillback, vermilion, tiger, china, and some yelloweye rockfish showed high site fidelity, being detected only at one or two nearby receivers for a full year. The range of vertical movements of yelloweye, quillback, vermilion, and tiger rockfish was small, ranging from only 2?3 m for the single tiger rockfish to 3?13 m for four of the quillback rockfish. Black and copper rockfish showed site fidelity that was intermediate between that of canary rockfish and the other species. Black and copper rockfish showed a wide range in vertical movements (10?35 m and 2?33 m, respectively) within a month. Our results suggest that small, no-take MPAs located on high-relief rocky reefs would provide minimal protection for canary rockfish, some protection for black and copper rockfish, and greater protection for quillback, vermilion, tiger, and some yelloweye rockfish. Abstract 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 designated for Oregon waters (337?1,502 ha). We tagged 6 black rockfish S. melanops, 31 canary rockfish S. pinniger, 9 yelloweye rockfish S. ruberrimus, 5 quillback rockfish S. maliger, and 2 copper rockfish S. caurinus, along with single specimens of china rockfish S. nebulosus, vermilion rockfish S. miniatus, and tiger rockfish S. nigrocinctus, and monitored their movements with a large (about 5,200-ha) receiver grid for over a year. Canary rockfish showed low site fidelity and wide-ranging movements that exceeded the scale of our detection grid and a wide range of vertical movements (up to 27 m). Quillback, vermilion, tiger, china, and some yelloweye rockfish showed high site fidelity, being detected only at one or two nearby receivers for a full year. The range of vertical movements of yelloweye, quillback, vermilion, and tiger rockfish was small, ranging from only 2?3 m for the single tiger rockfish to 3?13 m for four of the quillback rockfish. Black and copper rockfish showed site fidelity that was intermediate between that of canary rockfish and the other species. Black and copper rockfish showed a wide range in vertical movements (10?35 m and 2?33 m, respectively) within a month. Our results suggest that small, no-take MPAs located on high-relief rocky reefs would provide minimal protection for canary rockfish, some protection for black and copper rockfish, and greater protection for quillback, vermilion, tiger, and some yelloweye rockfish.Keywords: Oregon, site fidelity, Pacific rockfish, marine protected are

Buoyancy regulation and barotrauma in two species of nearshore rockfish

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 and acclimation rates in two ecologically different, yet congeneric, species: black rockfish Sebastes melanops and China rockfish S. nebulosus. We also conducted simulated-capture experiments to investigate the relationship between capture in a fishery, barotrauma from pressure change, and survival after release. Black rockfish acclimated faster than China rockfish to both increases and decreases in pressure, but both species were much slower to acclimate than other physoclists, such as Atlantic cod Gadus morhua. Black rockfish required up to 48 h to acclimate from 4 atmospheres absolute (ATA; depth equivalent of 30 m) to surface pressure and required up to 168 h to become neutrally buoyant at 4 ATA after starting from surface pressure. In contrast, China rockfish required over 250 h to become neutrally buoyant at 4 ATA after starting from surface pressure. All black rockfish exposed to a 3-ATA decrease in pressure during simulated capture had ruptured swim bladders. However, mortality from simulated capture and subsequent recompression was low; only 3.3 ± 1.7% (mean ± SE) mortality was observed after 21 d. In experiments with black rockfish, rapid recompression reversed visible barotrauma, suggesting that a quick return to depth could be used to minimize mortality of discarded black rockfish in nearshore fisheries.Keywords: buoyancy, barotrauma, Sebastes melanops, swimbladder, Sebastes nebulosu