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Homework Help: Do Harp Seal populations effect Atlantic cod?

  1. May 25, 2008 #1
    [SOLVED] Do Harp Seal populations effect Atlantic cod?

    The Atlantic cod population was an extremely abundant stock of primary economic importance to fishing communities throughout the Atlantic provinces. The Department of Fisheries and Oceans has stated that the collapse in Atlantic cod stocks can be attributed to overfishing. Others claim that the use of equipment that disturbs fish spawning sites on the ocean floor is primarily responsible, and still others argue that the harp seal, a predator of Atlantic cod, is responsible for this mass reduction in the cod population. One suggestion to help cod stocks recover is for large numbers of harp seals to be killed. Suggest some ways that marine biologists might study changes to the Atlantic cod population to determine whether the reduction of the harp seal population would be an effective solution.

    I searched up some stuff such as SEZ (Seal exclusion zone). But how do we determine whether the reduction of harp populations would effect the populations? But methods of mark-recapture?
  2. jcsd
  3. May 25, 2008 #2
    Good question!
  4. May 25, 2008 #3
    @above, Jerk! Haha just kidding!

    There we go!

    You could estimate population size for the cod and compare it to the population size of seals and to the fishing effort. Track these three variables over several years, and get some historical data as well. Theoretically, the fishing effort should be the same each year (likely governed by permitting or catch regulations) - but if fishing effort increases or decreases, look for a related change in cod populations. If cod population size is related to seal populations, an increase in seals should result in a subsequent decrease in cod populations, and visa versa. You could also measure cod demographics, like population age structure to get at the spawning habitat question. If there are relatively few young of the year cod, it would indicate a disruption in spawning. But, if there are many young cod, but few older individuals, it would indicate too many adults are being removed (either by fishing or the seals). A fish population should be dominated by young individuals with relatively old ones. Check and see the life expectancy of cod to determine what you should see in an undisturbed population.

    Make sure you use your own words ;)
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