Marine Salmon Interactions Program
Gamete Incompatibility in Salmonids
Scientists at the Auke Bay Laboratoryís (ABL) Little Port Walter Marine Station designed and implemented a study to
describe gamete incompatibility in Pacific salmon. Gamete incompatibility refers to the differential survival during
fertilization and initial embryo development of progeny from specific female-male mating combinations. Gamete
incompatibility is important because it can define speciation and may be an indication of inbreeding depression. The
study will provide valuable insight into the genetic process within and between stocks of steelhead and Chinook salmon
and will address fundamental issues that can drive conservation biology management decisions.
In May and August 2005, experiments were initiated using steelhead and Chinook salmon gametes in separate studies. In
each experiment, 75 single-pair matings of all possible crosses were made in a 5◊5 factorial design with three replicate
cells representing each female-male combination. Three blocks were completed using 5 different males and females for each
block representing a total 15 different males and females, and after replications, 225 parings for each species. Families
were assigned to incubator cells in a stratified random manner and incubated in vertical incubators. Survival data to
eyed-egg stage and to hatch was collected and analyzed using an ANOVA (analysis of variance) package in SAS
(data analysis software).
Initial statistical analysis for percent survival to the eyed-egg stage and hatch indicated that both steelhead and Chinook
salmon showed significant female-male interactions. These results indicate that certain female-male combinations either
inhibit fertilization or depress survival of early embryos. Further statistical analyses and analysis of biological samples
taken during the experiment will help determine factors that are responsible for this interaction.
By Andy Gray and John Joyce
Report to Purse Seine Task Force
Joe Orsi of ABLís Marine Salmon Interactions Program reported on ABLís Southeast Coastal Monitoring (SECM) project to the
Southeast Alaska Purse Seine Task Force in Ketchikan, Alaska, on 30 November 2005. This was a joint meeting of managers,
researchers, and users of the pink salmon resource in southeastern Alaska. The purpose of the meeting was to review the
2005 purse seine fishery in the region with respect to seasonal commercial harvest, adult escapements, and processing
capacity, and to discuss expectations for the 2006 season. The Purse Seine Task Force invited Orsi to present data from
epipelagic ichthyofauna trawl surveys conducted by SECM that provide reliable forecast of pink salmon adult returns based
on juvenile salmon indices.
The overview of the SECM project included preliminary results on forecasting chum salmon and a discussion of the possible
ecological consequences of localized warming in the Southeast Alaska region of the Gulf of Alaska ecosystem. In 2004-05,
SECM research documented anomalous warm waters in the area that appeared to trigger an earlier seaward migration of
juvenile salmon; additional research in the region in late August in 2005 showed a northward range expansion of southern
species such as Pacific sardine and Humboldt squid. There were additional corroborative reports at the meeting from purse
seine fishers who also experienced warmer water temperatures than normal and had large catches of Pacific sardine throughout
southeastern Alaska in July and August.
Documenting unusual and anomalous oceanographic conditions from commercial fishers in the region raises the prospect of
utilizing this untapped source of data in the newly developing Southeast Alaska Ocean Observation System (SEAOOS).
Integrating relevant data from research findings and the commercial fishing industry can help develop a better understanding
of how ecosystems fluctuate.
By Joe Orsi and Alex Wertheimer
OND2005 quarterly sidebar
Research Reports Oct-Dec 2005