An individual‐based life history and population dynamic model for the winter–spring dominant copepod of the subarctic North Atlantic, Calanus finmarchicus, is coupled with a regional model of advection for the Gulf of Maine and Georges Bank. Large numbers of vectors, each representing individual copepods with elements for age, stage, ovarian status and other population dynamic variables, are carried in a computation through hourly time steps. Each vector is updated at each time step according to development rate and reproductive functions derived from experimental data. Newly spawned eggs are each assigned new vectors as needed. All vectors are subject to random mortality. Thus, both life history progression and population dynamics of C. finmarchicus are represented for the temperatures in the Gulf of Maine–Georges Bank region in the active season. All vectors include elements representing depth, latitude and longitude. This allows coupling of the population dynamics to the tide‐ and wind‐driven Dartmouth model of New England regional circulation. Summary data from the physical model are used to advance vectors from resting‐stock locations in Gulf of Maine basins through two generations to sites of readiness for return to rest. Supply of Calanus stock to Georges Bank comes from all of the gulf and from the Scotian Shelf. The top of the bank is stocked from western gulf basins; the North‐east Peak is stocked from Georges Basin and the Scotian Shelf. All sources contribute to stock that accumulates in the SCOPEX gyre off the north‐west shoulder of Georges Bank, explaining the high abundance recurrently seen in that region. There is some return of resting stock to Wilkinson Basin in the western gulf, but other basins must mostly be restocked from upstream sources to the north‐east.
[1] A three-dimensional model of the California Current System (CCS) from 35°N to 48°N extending offshore to 134°W is coupled with a four-component trophic model. The model reproduces many conspicuous characteristics in the CCS, including: complex, filamentary, mesoscale surface features seen in the pigment and temperature from satellite imagery; wind-driven coastal upwelling at appropriate spatial and temporal scales; and the close correlation between prominent features seen in pigment and those in temperature observed by satellites (Abbott and Zion, 1985). Statistical estimates of the characteristic spatial scales of variability, as calculated from the coupled, nested model, agree with those previously estimated from satellite images (for both surface temperature and pigment Abbott, 1988, 1994)). Model estimates of the characteristic temporal scales of variability, from decorrelation times, agree with those previously estimated from satellite images. Typical model decorrelation times lie between 2 and 4 days, in agreement with calculations from earlier sequences of (Coastal Zone Color Scanner (CZCS) and advanced very high resolution radiometer (AVHRR)) satellite images Abbott, 1988, 1994).
On the basis of observations of Weddell seals (Leptonychotes weddellii Lesson) made in the course of studying shallow-water benthic communities in McMurdo Sound, Antarctica, we suggest that caching and/or defence of uneaten food may be a strategy practiced by this animal. Such a phenomenon is uncommon but taxonomically widespread among vertebrates. Depending on circumstances, it is termed hoarding, caching, or storage and may be short- or long-term, include defence of the resource, or have other variable expressions, with the common threads being deferred consumption and deterrence of consumption by others (Vanderwall 1990). Many vertebrate taxa exhibit hoarding behaviour, including rodents (e.g. Sciuridae), carnivores (e.g. Canidae, Felinidae) and birds (e.g. Corvidae, Picidae). No form of food caching, to our knowledge, has ever been reported in a wild pinniped.
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