Alaska Fishery Research Bulletin Issues, Vol.3 No. 2 - Winter 1996

Evaluation of Scale Pattern Analysis for Upper Cook Inlet Sockeye Salmon Stocks

David L. Waltemyer, Brian G. Bue, and Kenneth E. Tarbox - Vol. 3(2):69-80. 1996.

We evaluated scale pattern analysis, specifically linear discriminant function analysis and bivariate normal-density contour plots, as a tool to identify sockeye salmon Oncorhynchus nerka stocks returning to Upper Cook Inlet. Overall mean classification accuracy for 3-way, Kenai-Kasilof-Susitna River discriminant models ranged from 62 to 75% for the years 1983-1988. Bivariate normal-density contour plots of scale variables revealed a lack of consistency in size and shape and had significant overlap among stocks. Significant temporal and sexual intrasystem differences in scale variables were detected. Scale pattern has not provided the precision needed to effectively manage salmon stocks returning to Upper Cook Inlet.

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Effects of Formalin and Alcohol Preservation on Lengths and Weights of Juvenile Sockeye Salmon

Patrick A. Shields and Stan R. Carlson - Vol. 3(2):81-93. 1996.

Preserving fish can induce changes in fish tissue and structure that affect subsequent measurements of length and weight. We conducted 3 different experiments to quantify these changes and allow correction factors to be used as needed in analyses of fish growth and production. The experiments were designed to (1) determine temporal variation in the length and weight of juvenile sockeye salmon Oncorhynchus nerka as a result of storage in either 10% neutral freshwater-buffered formalin or 95% ethanol; (2) describe the amount of observed variation in length and weight measurements that can be attributed to reader variability; and (3) formulate conversion equations that allow for back-calculation to fresh lengths and weights. Fish preserved in alcohol for 70 d revealed a mean weight loss of 0.68 g after 16 d (19.7% of mean fresh weight; P < 0.001) and then appeared to stabilize through 70 d (P > 0.05). Length initially decreased by 1.41 mm after 16 d (2.19% of mean fresh weight; P < 0.0001), remained stable through 42 d, and then increased significantly (P < 0.0001) by day 70. Storage of fish in formalin produced various results. One experiment revealed a nonsignificant change in length (P = 0.114) after 70 d in the preservative; weight increased 0.24 g (7.12%; P < 0.0001) after 16 d of preservation, but then stabilized through 70 d. Additional formalin effects ranged from a minor length loss (P < 0.0001) and a substantial weight gain (P < 0.0001) after 106 d of storage to a significant (P < 0.001) loss in length after 30 d and continued loss through 99 d. Although a weight gain occurred after 30 d of preservation (P < 0.0001), no significant difference from fresh weight was found after 99 d. We examined the amount of variation in these results that may be attributed to reader differences. For the formalin group, maximum differences between readers were 3.5% (P < 0.0001) for lengths and 6.5% (P < 0.0001) for weights. For the alcohol group, differences were 1.9% (P < 0.0001) for lengths and 6.4% (P < 0.0001) for weights. Instructing readers on standardized blotting methods resulted in a maximum difference between readers of only 2.5% for weight measurements. Conversion equations that allow for back-calculation to original live lengths and weights were developed.

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New North American Records of the Northeast Pacific Scorpaenids Adelosebastes latens and Sebastes glaucus

James Wilder Orr and David C. Baker - Vol. 3(2):94-102. 1996.

The Aleutian scorpionfish Adelosebastes latens Eschmeyer, Abe, and Nakano, 1979, and the gray rockfish Sebastes glaucus Hilgendorf, 1880, are reported from new North American records from the Aleutian Islands, Alaska. Both records represent significant range extensions of about 2,200 km for each species. New diagnoses and notes on morphology, habitat, and species associations are provided for each species.

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Ovarian Energy Content of Pacific Herring From Prince William Sound, Alaska

A. J. Paul, J. M. Paul, and E. D. Brown - Vol. 3(2):103-111. 1996.

Ovarian energy content (OEC; measured in kilojoules) of ripe whole ovaries and per gram of ovary wet weight (OEC·g-1) were examined for Pacific herring Clupea pallasi from Prince William Sound, Alaska. Specimens were collected in 1995 and 1996. The OEC of whole ovaries was related linearly to whole body weight, but OEC·g-1 of ovary was not. Just prior to spawning OEC was typically between 5 and 7 kJ·g-1 of ovary. There were no significant differences in OEC·g-1 of ovary between groups of females from different capture sites in the 1995 collections, but in 1996 there were small but significant differences in OEC values related to capture site. When the OEC values from all fish collected in 1995 were pooled and compared to all those collected in 1996, there was no significant difference in OEC·g-1 of ovary between years. The number of ova present just prior to spawning exhibited no clear relationship to OEC·g-1 of ovary. About 97% of OEC was expended during spawning. The OEC of whole ovaries was used to estimate the energy from herring spawn added to Prince William Sound beaches from 1988 to 1995. Since 1989, when there was a massive oil spill, the annual amount of energy added to the Prince William Sound ecosystem by herring eggs has decreased from 68 x 109 kJ to 10 x 109 kJ in 1995, which in addition to being a concern for recruitment, could also be important to species relying on herring spawn as an energy source.

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Use of the Littoral Zone by Introduced Anadromous Salmonids and Resident Trout, Margaret Lake, Southeast Alaska

Mason D. Bryant, Brian J. Frenette, and Katharine T. Coghill - Vol. 3(2):112-122. 1996.

Construction of a fish pass around a barrier falls allowed at least 5 species of anadromous salmonids to colonize the Margaret Lake watershed, more than doubling the number of fish species in the lake. Juveniles of these anadromous salmonids, primarily coho Oncorhynchus kisutch and sockeye O. nerka salmon, rapidly and successfully colonized the littoral zone of Margaret Lake. Coho salmon fry and parr were the predominant salmonid species in the littoral zone after the fish pass was opened, and sockeye salmon fry were captured in both the littoral and pelagic zones. Although relatively few cutthroat trout O. clarki were captured throughout the study, they were the primary resident salmonids using the littoral zone before the fish pass was opened and were continually captured in the littoral zone throughout the study. Diel catch varied among species and was inconsistent from year to year. Numbers of fish captured at each site appeared to be associated with the geographic source of recruitment: stream outlets for coho salmon and planting location for sockeye salmon. Growth rates of coho salmon juveniles appeared to be greater later in the summer, whereas growth of sockeye salmon appeared to be greater during midsummer.

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Habitat and Depth Distribution of the Red Sea Cucumber Parastichopus californicus in a Southeast Alaska Bay

Shijie Zhou and Thomas C. Shirley - Vol. 3(2):123-131. 1996.

A field survey of red sea cucumber Parastichopus californicus distribution was conducted June 18-22, 1991, using a manned submersible in Barlow Cove, Southeast Alaska. The density of sea cucumbers counted in transects averaged 20.8 individuals·ha-1 in the inner, 70.9 in the middle, and 103.7 in the outer stratum of the cove. Six types of substrata were encountered: mud/sand, debris, rock, shell, rock wall, and algae. Sea cucumbers were found at almost all depths from the intertidal zone to as deep as 183 m. Higher densities were encountered in 2 distinct depth zones: above 60 m and between 100 m and 150 m. This bimodal distributional pattern was attributed to the depth distribution of the rock wall substrate, which supported the highest density of sea cucumbers at 234·ha-1. The higher densities of sea cucumbers along the nearly vertical rock walls are unexplained; rock walls may be preferred to the unstable nature of other substrates on the steeply sloped wall of the cove, or they may be selected for spawning.

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Male Tanner Crab Carapace Widths at Previous Intermolt Estimated from Laboratory Growth, Kachemak Bay, Alaska

A. J. Paul and J. M. Paul - Vol. 3(2):132-135. 1996.

Laboratory growth observations of Tanner crab Chionoecetes bairdi from lower Cook Inlet suggest that only males greater than or equal to 119 mm in carapace width (CW) could recruit to the legal size of 140 mm CW in a single molt. Back-calculated estimates of previous CWs indicated 84% of a sample of males captured in the fishery had CWs of 119-139 mm during their previous intermolt and 16% had CWs greater than or equal to 140 mm. This suggests that some crabs greater than or equal to 140 mm CW molt, but most of the harvested crabs were of sublegal size prior to their last molt.

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Online Bulletin's New Feature

Robert L. Wilbur and Kurt E. Savikko - Vol. 3(2):136. 1996.
(No Abstract) Full Editorial:

The Bulletin is now fully electric, literally, instead of just figuratively. You can access the Bulletin from the Alaska Department of Fish and Game's homepage: http://www.adfg.alaska.gov. The Bulletin is available in Adobe® Acrobat® Portable Document Format (PDF), which allows us to provide it in a fully formatted layout. It mirrors previous hard-copy versions but is ready for electronic viewing and printing. All that is required to use these PDF documents is a free Adobe viewer available from a link on our website or directly from Adobe. After installation of the viewer, direct access to the PDF documents is only a click away.

For now, the Bulletin will continue to be anchored in its paper copy. This means we will continue to produce printed issues, and the online issues will be posted issue by issue concurrent with the printed distribution. We may in the future become exclusively electronic, which would eliminate paper production costs and provide more timely access. That is, electronic-only journals are not posted by issues but are instead posted paper by paper (whenever a paper is ready, it is posted). This eliminates a paper's delay while the rest of the issue is assembled, which would benefit both authors and readers.

The online Bulletin, however, now offers a significant feature - a postnote - not present in the paper version. The postnote will be appended to the end of some papers after they are published (e.g., see online vol 3, nr 1, p 44) and will contain abbreviated post-publication notes that may be important to the readers of that paper, that is, important subsequent developments they might otherwise overlook or not discover until much later. As such, the postnote is intended as a service to our online readers, one that hopefully will increase their timely access to subsequent and specifically related information.

For example, if there was a particularly pertinent follow-up publication, that publication might be noted in the postnote, and if that related paper was published in a subsequent issue of the Bulletin, it would be electronically linked so the reader could immediately access that paper. The postnote will be especially useful in flagging and accessing subsequently published errata or challenges and rebuttals. In other cases, we might include a reader's contribution of unpublished findings or observations that would provide useful information or insights. However, we do not envision the postnote developing the demeanor of a chat room or bulletin board, so contributions will be carefully examined for their scientific importance and relatedness before acceptance and posting.

For most of our readers the postnote will be a new, unfamiliar feature in scientific reporting. However, we believe that postnotes will enhance the utility of our online service, so we especially encourage our readers to submit items for consideration and possible posting. Past authors are also encouraged to submit relevant follow-up items.

If you have an item you would like to have considered for inclusion as a postnote, please submit it to the editor at the address noted on the inside cover (or email: bobw@fishgame.state.ak.us). Please remember to cite the article your item references. We will notify you shortly thereafter of our decision and of any recommended changes. Inclusions will be filed chronologically within a postnote and include the contributor's name(s) and address. Additions to a postnote will be posted within several days of their approval.

Note: Email address in this article is outdated. Links and email addresses in PDF documents may be outdated.

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