Analysis of habitat features and abundance of young-of-the-year fishes off of the central Oregon coast

Over the last several years, the Northwest Fisheries Science Center, in collaboration with the Pacific States Marine Fisheries Commission and Oregon State University, has been sampling young-of-the-year groundfishes and other small demersal fishes along the Newport Hydrographic (NH) line. An important question concerning these surveys is whether the NH line is representative habitat for demersal fishes along the central Oregon coast. Answering this question would help determine whether adding additional sampling lines to the long-term sampling project would be needed. In this analysis, beam trawl tows were taken from 16 stations along three sampling lines off of the central Oregon coast in September of 2012. In addition, high-definition videos were taken from these tows. From the beam trawl sampling there were no significant differences found in fish assemblages, dissolved oxygen, or temperature based on line, but there was a significant difference in communities and temperature based on depth. No clear pattern was found among the soft-sediment habitat variation. By comparing fish community composition and habitat across these transects, we addressed the overall question of whether the NH line is representative of a larger section of the central Oregon coast.This project is part of ongoing research, which has been extended to include temporal variation. Dr. Lorenzo Ciannelli has also been brought onto this project as of Fall 2015

Using In Situ Video Analysis to Assess Juvenile Flatfish Behavior Along the Oregon Central Coast

We examined the feasibility of using a video beam trawl system to assess behavioral responses of juvenile flatfishes in relation to co-occurring habitat features, most notably dissolved oxygen (DO) concentrations. Sixteen samples were collected along a cross shelf transect in the central Oregon coast during summer 2008. We found that juvenile fish reaction duration, defined as the time in seconds from first reaction to capture, decreased with decreased DO. However, other variables such as bottom water temperature, fish size, and fish species composition by site are potentially confounding factors of the analysis. The dominant flatfish species shifted from English sole (Parophyrs vetulus) to Pacific sanddab (Citharichthys sordidus) with increased depth. Escape behavior varied from “burying” in the shallows, to “hovering” at mid-depth stations, and “running” at the deepest site. Collectively, our results suggest that the video beam trawl effectively monitor behavioral metrics and community composition of nearshore flatfish assemblages.This is the publisher’s final pdf. The published article is copyrighted by the Scripps Institution of Oceanography and can be found at: http://www.calcofi.org/Keywords: juvenile, performance, hypoxia, flatfish, behavior, in situ vide

Lost in plain sight : the evolution of Oregon's nearshore groundfish trawl fleet

The West Coast groundfish industry collapsed in 2000, but it recovered through the efforts of regulators, scientists and the fleet. Now it is working to rebuild the market and reconnect with a formerly active fishing ground along Oregon’s nearshore. In this report, we define nearshore as the shelf that extends seaward to a depth of 110 fathoms (660 feet). The nearshore is of particular value to flatfish groundfish as a nursery and as settlement habitat. It’s also an important area for the recruitment of many other species of groundfish, which tend to settle within the region, making it a desirable spot for Oregon’s groundfish trawlers (1, 2, 3). Despite this, little research has been conducted on the shallow portions of the shelf (around 30 fathoms – or 180 feet – deep). Many of the details of the ecology, health and processes in these habitats remain poorly understood. The knowledge of people who fish within this region, the challenges they face, and the opportunities they can glean from the reopening of nearshore fishing grounds are also insufficiently explored. With this in mind, our study aimed to gather and synthesize the experiential knowledge of nearshore commercial fishermen into a comprehensive and insightful picture of this place, the fishery and the people who engage with it. Connecting narratives and information on fish stocks, their management and the fleet presents an opportunity to holistically understand the health, value and future of this nearshore fishery. We began by gathering data from commercial trawl logbooks and fish tickets. We also conducted semi-structured interviews with industry participants. Our work provides an opportunity to use this local ecological knowledge (LEK) to enhance scientific ecological knowledge (SEK) and inform regional management, users and citizens about Oregon’s nearshore

Studies of juvenile salmonids off the Oregon and Washington coast, 1981

The Oregon State University School of oceanography conducted purse seining surveys of juvenile salmonids in the ocean off Oregon and Washington during spring and summer 1981. The objectives of the field study were: 1) To collect information on the distribution and abundance of juvenile salmonids off Oregon and Washington; and to relate distributional patterns to oceanographic conditions and forage availability; 2) To make observations on fish movement through recovery of fish marked with coded wire tags and fluorescent pigment; 3) To collect juvenile salmonids for studies of growth, condition and food habits; 4) To assess the composition, abundance, and food habits of nekton co-occurring with juvenile salmonids

Evaluating off-bottom sweeps of a U.S. West Coast groundfish bottom trawl: Effects on catch efficiency and seafloor interactions

In the U.S. West Coast groundfish bottom trawl fishery, lengthy sweeps (>85 m) that maintain seafloor contact are traditionally used. While these sweeps are effective at herding groundfishes, their bottom tending characteristics increase the potential to cause seafloor disturbances, and injury and unobserved mortality to benthic organisms. In this study, we examined if changing from conventional to modified sweeps (with sections elevated 6.5 cm off bottom) would affect catch efficiency of target groundfishes and seafloor interactions. We used a DIDSON imaging sonar to observe how each sweep configuration interacted with the seafloor. An altimeter was periodically placed on the modified sweep to measure height off bottom. Results detected no significant catch efficiency effect of changing from conventional to modified sweeps. The DIDSON and altimeter data showed the modified sweeps exhibit elevated sections where infaunal and lower-profile epifaunal organisms can pass under without disturbance. Results demonstrate that seafloor interactions can be substantially reduced using elevated sweeps in this fishery without impacting catch efficiency. Further, findings from this research could be potentially applicable to other fisheries nationally and internationally.acceptedVersio

Illuminating the Headrope of a Selective Flatfish Trawl: Effect on Catches of Groundfishes including Pacific Halibut

This study evaluated how illuminating the headrope of a selective flatfish trawl can affect catches of groundfishes, including Pacific Halibut Hippoglossus stenolepis, in the U.S. West Coast limited‐entry (LE) groundfish bottom trawl fishery. Over the continental shelf, fishermen engaged in the LE bottom trawl fishery target a variety of flatfishes, roundfishes, and skates. Green LED fishing lights (Lindgren‐Pitman Electralume) were used to illuminate the headrope. The lights were grouped into clusters of three, with each cluster attached ~1.3 m apart along the 40.3‐m‐long headrope. Catch comparisons and ratios of mean fish length classes were compared between tows conducted with (treatment) and without (control) LEDs attached along the trawl headrope. Fewer Rex Sole Glyptocephalus zaphirus, Arrowtooth Flounder Atheresthes stomias, and Lingcod Ophiodon elongatus were caught in the treatment than in the control trawl, though not at a significant level. Pacific Halibut catches differed between the two trawls, with the treatment trawl catching an average of 57% less Pacific Halibut. However, this outcome was not significant due to a small sample size. For Dover Sole Microstomus pacificus 31–44 cm in length and Sablefish Anoplopoma fimbria 43–61 cm in length, significantly fewer fish were caught in the treatment than in the control trawl. On average, the treatment trawl caught more rockfishes Sebastes spp., English Sole Parophrys vetulus, and Petrale Sole Eopsetta jordani, but not at a significant level. These findings show that illuminating the headrope of a selective flatfish trawl can affect the catch comparisons and ratios of groundfishes, and depending on fish length and species the effect can be positive or negative.publishedVersio

The Efficacy of Illumination to Reduce Bycatch of Eulachon and Groundfishes Before Trawl Capture in the Eastern North Pacific Ocean Shrimp Fishery

This study examined the extent that eulachon (Thaleichthys pacificus) and groundfishes escape trawl entrainment in response to artificial illumination along an ocean shrimp (Pandalus jordani) trawl fishing line. Using a double-rigged trawler, we compared the catch efficiencies for ocean shrimp, eulachon, and groundfishes between an unilluminated trawl and a trawl illuminated with 5 green LEDs along its fishing line. Results showed a significant reduction in the bycatch of eulachon and yellowtail rockfish (Sebastes flavidus) in the presence of LED illumination. As eulachon are an Endangered Species Act listed species, this finding provides valuable information for fishery managers implementing recovery plans and evaluating potential fishery impacts on their recovery and conservation. For other rockfishes (Sebastes spp.) and flatfishes, however, we did not see the same effect as the illuminated trawl caught similarly or significantly more fishes than the unilluminated trawl. Prior to this research, the extent that eulachon and groundfishes escape trawl capture in response to illumination along an ocean shrimp trawl fishing line was unclear. Our study has provided results to fill that data gap.acceptedVersio

The Efficacy of Illumination to Reduce Bycatch of Eulachon and Groundfishes Before Trawl Capture in the Eastern North Pacific Ocean Shrimp Fishery

This study examined the extent that eulachon (Thaleichthys pacificus) and groundfishes escape trawl entrainment in response to artificial illumination along an ocean shrimp (Pandalus jordani) trawl fishing line. Using a double-rigged trawler, we compared the catch efficiencies for ocean shrimp, eulachon, and groundfishes between an unilluminated trawl and a trawl illuminated with 5 green LEDs along its fishing line. Results showed a significant reduction in the bycatch of eulachon and yellowtail rockfish (Sebastes flavidus) in the presence of LED illumination. As eulachon are an Endangered Species Act listed species, this finding provides valuable information for fishery managers implementing recovery plans and evaluating potential fishery impacts on their recovery and conservation. For other rockfishes (Sebastes spp.) and flatfishes, however, we did not see the same effect as the illuminated trawl caught similarly or significantly more fishes than the unilluminated trawl. Prior to this research, the extent that eulachon and groundfishes escape trawl capture in response to illumination along an ocean shrimp trawl fishing line was unclear. Our study has provided results to fill that data gap