This lecture features two fisheries, both of which are now in great decline or completely stopped. These are the cod and the whales. Both are marked by a long history of development that parallels the history of many societies. It is especially interesting to consider the attitudes towards the species involved from the prospective of our great-great-grandparents versus our feelings today.
One hundred years ago (even fifty years ago) the great whales were viewed as a natural resource. Oil from whales played a crucial role in lubricating and lighting the early industrial revolution. This change from subsistence fisheries for whales to industrial whaling has almost doomed these magnificent mammals. It is interesting to note that fashion also played a role in the precusor to the underwire bra and the tight corset of Victorian times, both of which used baleen from the filtering apparatus of the baleen whales.
Today the viewpoint is completely changed. Although there are a few cultures that still view whales as part of their culinary inheritance, at this point in history there are only a few aboriginal groups such as Eskimos that are taking whales for food.
Cod, in particular the Atlantic cod, Gadus morhua, has been a staple food for the expansion of western civilization, or in some recent revisionist views, the plague of exploition and colonization that occured from 1492 until the recent past. It is an interesting side note that there is good evidence that Basque fishermen were on the Grand Banks of Newfoundland well before Columbus. Fishermen, however, want to keep their secret grounds and did not let their secret new land be known. It is interesting to speculate that both Columbus and the other Genoan explorer Cabot, who first reported the existance of the Grand Banks to the king of England, knew of the existence of the new lands from these fishermen.
Cod became the wealth of New England and the harbinger of both the American and French Revolution. The availabity of cheap salt cod was crucial for the slave based sugar plantation economy in the the 1600-1800 Caribbean. This commerce also drove a large rum industry in New England that fueled the ability to dismiss linkages to Britain.
In todays world, unfortunately, the great cod
fisheries after centuries of sustained exploitation are collapsing under
the pressure of modern politics and the economics of fishing. The cod fisheries
on the Grand Banks off New England and all of the great Canadian fisheries
are now closed. Cod that is an important fish in cusines ranging from
English fish and chips to bacalhua de coco in Brazil is now in trouble. For a excellent history of the cod see Mark Kurlansky's recent book "Cod: A biography of the fish that changed the world."
Studying Behaviour: The problem of "fish" and men. The problem with understanding either cod or whales, and for that matter our impact on them, is fundamentally tied to the understanding of behavior. As in the last lecture, the question is how different animals use the environment. This of course, includes humans when fisheres are considered.
How do cod behave? Cod are demersal fish that
live on shallow (<100 m) banks for the most part. The attachment to
the bottom topography, i.e. shelves and banks, defines demersal. The current
understanding of cod biology is that the adults choose a spawning
location that traps the young on the banks. This suggests that these fish have adapted by a combination of evolution and basic adaptabilty to use the physical and biological attributes of these banks around the Atlantic. The reason for their success is in the large phytoplakton production of these banks and the bank's ability to sustain large copepod populations for the larval cod and secondary fish prey for the adults (including young cod).
How do the whales live?
Whales are very difficult to study. Perhaps
one of best early studies of a whale is the novel "Moby Dick" by
Herman Melville. One of the reasons it stresses English majors is the detail
it includes on sperm whale biology. Of course, this view is slanted towards
the fishery. This tale is from the viewpoint of the exploitation of the
whale. The modern appreciation of sperm whales suggests that they are much
like swordfish in where they are found. This is probably tied to fact that
both species are major predators on squid. The migration pathways, however,
seem to be very different. A problem with this conclusion is
that the evaluation depends on sources that depend on our own behavior. The problem is that our knowlege of the the behaviour of either the cod or the whales depends on our own fisheries activities or those in the past.
Example of how whales work their environment, humpbacks and bubbles, and long range acoustics, i.e how far can whales commuicate?