RECORD HIGH LOBSTER LANDINGS IN SOUTHWEST NOVA SCOTIA - DOES THIS DISCREDIT THE “STARVATION” THEORY?
Letter received via email Feb. 15, 2000:
I've read most of your article on starving fish. Having been involved in the fishing industry for 25 years, a lot of changes have taken place. TAC's go up and down over a period of time. Most people will confess that as of late there seems to be more of the fisheries in decline. Our herring fishery in South West Nova has seen two of the last ten years, where the fat content of the fish was abnormally low. In the following years things returned to normal. DFO science felt that an average level of spawning had taken place in those years, mother nature compensates in ways we do not understand. One big counter argument to your theory is the lobster fishery in District 34. Lobsters are bottom scavengers and their numbers have been increasing since the late 70's. There is no clear explanation for this, fewer predators and an increase in water temperature may of helped. You need to study this issue alot more and how species are inter-dependent on each other. Don't always take the written form as gospel, even scientist like to bend facts to their beliefs. Fish off the southern tip of Nova Scotia are not starved.
This letter raises many very good points, the main one being a question that I puzzled over for a LONG time - the lobsters ... “One big counter argument to your theory is the lobster fishery in District 34” (Southwest Nova Scotia). He’s right. I know the lobster fishermen. Lobster landings in this area have increased dramatically in the last decade, with another substantial rise last fall, up 25% or more from the year before.
IF "EVERYTHING" IS IN DECLINE, HOW CAN THE NUMBERS OF LOBSTERS BE INCREASING?
In my theory about what the ocean would look like as it was starved, one of the principles that appeared logical was that as higher predators disappeared, their usual prey, creatures that feed lower in the system, especially those that feed on plankton alone, would enjoy an advantage for a while because of the lack of predation. Groundfish stocks in this area have been in a steady decline during the recent rise of the lobsters, and the letter writer does acknowledge “fewer predators” as part of the likely explanation. (Groundfish like cod eat a lot of baby lobsters.) So maybe last year’s “sharp” increase in lobster numbers just reflects another corresponding “sharp” decline in the groundfish, in a now severely unbalanced system. The system is very complex with many inter-dependent species and intense fishing has caused it to become increasingly out-of-kilter. The downhill course for the ocean is not smooth but bumpy since so many factors interact with one another; the (temporary) rise in crustaceans, today's glut of lobsters; I think it is just one of the “bumps” on the way down.
Still, all those lobsters present a bothersome question...how can such great numbers of “scavengers” live and reproduce in a situation of supposed “food shortage?” What do they eat?
Lobsters are not just “scavengers,” in a pinch they can survive as plankton feeders. And plankton feeding crustaceans will be one of the last things to disappear. Here is a little excerpt from my book:
“ Whether or not crabs and lobsters could be put in this category (filter feeders) was a bit doubtful at first, since they do have those mean-looking claws and I, at least, had always understood that they were “opportunistic” feeders. I thought that “opportunistic” meant that if there was an opportunity to kill and eat something, they took it, and also that if there was an opportunity to eat some dead thing that they found lying on the bottom, they would take advantage of that too. A closer look at these animals, however, reveals the fact that they must also be able to take advantage of the “opportunity” to be filter feeders and survive on the plankton in the water.
Evidence to support this last statement comes from the description of the lobster’s habits that is commonly included in DFO lobster Stock Survey Reports. “The larvae spend 30-60 days in the plankton, before settling to the bottom and seeking shelter. For the first 2-3 years of benthic life, lobsters remain in or near their shelter to avoid the small fish that feed on them. As they grow, and have less chance of being eaten, they move about and become catchable by lobster traps.” Those little lobsters in the first few years of their life hide really well. In a lifetime of living on the coast of Nova Scotia, and going lobster fishing more than once, I have yet to see a lobster that was small enough to have been less than 3 or 4 years old (under 4 or 5 inches in length). So if baby lobsters spend their early years hiding in little holes, how do they grow, and what do they eat? Once they have consumed whatever crumbs were available on the bottom, their only option is to live on plankton. This ability to survive only on seawater is also well-known in adult lobsters. A local fisherman told me of a year when he forgot about a crate of banded lobsters for about eight months. When he found them they were still alive and “snapping.” Finfish, in contrast, need to be fed solid food on a regular basis. The salmon that are reared in aquaculture pens, for example, need to be fed several times a day. This is why it is reasonable to classify lobster and crab with the plankton feeders.”
(Another question comes to mind...if they are “filter feeders” where is the “filter?” That sort of detailed lobster physiology I could not find written anywhere, but I have eaten many a lobster. Running up the sides of the body, just beneath the carapace shell, are some soft, feathery structures. If, and this is only speculation on my part, those organs are the ones that filter the water, they would appear to be adapted to trap particles instead of just absorb oxygen - they really do not resemble the texture of the gills of fish - more like the “baleen” of plankton feeding whales? I don’t claim to know this for a fact - DON’T HOLD ME TO IT!, just wondering, that’s all...I do know that if all of a lobster’s food goes in through the mouth it can wait an amazingly long time between meals.)
ARE THE LOBSTERS GETTING ENOUGH TO EAT?
The rate of growth is the surest indication of the availability of food. For the fish species with “weight-at-age” data, malnutrition becomes obvious when the number drops significantly. This is documented for some, but not all, fish species (done by counting rings on a little bony piece out of the ear) and those in the waters off Southwest Nova Scotia (Bay of Fundy, George’s Bank) do show serious declines, so I don’t think a general statement can be made that “fish off the southern tip of Nova Scotia are not starved.” At the very least, it can be argued that the groundfish are “hurting.” They are underweight, in poor “condition.”
There is no reliable method that I know of to determine the age of a lobster, except perhaps by raising it in captivity from a larva. If they are getting less to eat, however, there should be subtle signs. Here is another quote from my book regarding Southwest Nova Scotia lobster:
“There are tiny little whisperings of trouble though, I have been informed that during the 1998-1999 winter season there was an increase in the number of complaints from buyers about “short-meat” lobsters. Lobsters normally moult (shed their shell, put on a new and bigger one, and then the flesh inside grows to fill the new size) in the summer. Since last year’s catch appeared not to be as “full” as expected, it was speculated that maybe the warmer summer water had triggered a “second moult” in the lobsters. Impossible. Not enough food in the water to gain weight as quickly as usual? Most likely explanation.”
Another recent observation about lobster has been an “increase in number of undersized berried females.” The quote comes from the FRCC’s Lobster Report (included in a supplement to the Yarmouth Vanguard, Nov. 16, 1999). The point at which a creature like a lobster first becomes fertile gives some indication of it’s age - the age of puberty. This observation (“roe” in smaller-than-usual female lobsters) has also been noted by myself and others that eat them. If they are smaller than usual when they first mature, they are growing more slowly than normally, which indicates a decline in the amount of food that is available to them. (This implies declining “weight-at-age” in lobsters.) The same thing (roe in smaller specimens) has been noted in recent years in species like cod and haddock which are known to be suffering from declining weight-at-age. It is very important to look at the overall picture for common themes.
One more note on the nutritional status of lobsters in Southwest Nova Scotia. During the past season, on several occasions I have eaten lobsters the same day that they were caught. Years ago, the “vein” in the tail (actually bowel) of a freshly caught lobster would always have some dark fecal material in it. A lobster that had been held in a crate or a pound for any length of time, however, would often have a perfectly clean “vein.” This being because it had taken in no solid food recently - subsisting only on “seawater” or plankton. Freshly caught lobsters now often have perfectly empty bowels...10 or 15 years ago, in my experience, this was never the case. (Some of today’s lobsters, of course, do have fecal matter in them - the ones that got in the trap first and had the opportunity to eat the bait.) It has also been told to me, merely by “word of mouth,” that some local lobster pound owners have been of the opinion recently that the lobsters are “starving.” And protein levels, at least in the “offshore” lobsters, have been dropping. Hungrier lobsters would also be more interested in the bait and therefore easier to catch - no?
WHY ARE THERE MORE LOBSTERS IN SOUTHWEST NOVA SCOTIA THAN ELSEWHERE?
The last couple of decades of lobster fishing in Southwest Nova Scotia have been exceptionally profitable. Other fisheries go into decline, including even lobster in Atlantic Canada overall, but Southwest Nova seems to be immune to this trouble. This area will be one of the last to go into decline because it’s natural physical characteristics have made it an exceptionally nutrient-rich part of the ocean. Between the mouth of the Bay of Fundy (highest tides in the world, therefore huge intertidal zones which contribute significantly) and George’s Bank (very favorable natural combination of shoal and currents), the waters off the southern tip of Nova Scotia are in an ideal location for marine life. Fish like cod and haddock have long been known to grow faster in these waters than in other areas - but this part of the ocean that formerly produced “fat” fish is now producing thin ones, there are fewer groundfish, salmon, gaspereau, eels, and sharks...the overall signs point to starvation becoming a real problem here as well. Southwest Nova Scotia does not exist inside a magic bubble - fisheries are collapsing worldwide - it’s only a matter of time...I’m afraid we could be riding the “last wave.”
p.s. My suggestion makes logical sense and should do no harm--Feed the Fish!
(Lobster photo above - courtesy OAR/NURP)