It’s interesting to note what you say Stores, but I think it gives further credence to short term feeding on specific species or prey groups due to availability. Over the last few years I\'ve been working a lot on inshore crab and lobster populations, and a few limited surveys prior to this (10 years ago+).
The data clearly show that off the east Yorkshire coast 10 years ago you could count on the fingers of one hand the number of velvet crab caught by a single fisherman per year (4 or 5), presently I\'m averaging between 5 or 6 per pot, and based on 6 fleets (20 pots per fleet) I can catch 100kgs per day and on a good day 10 boxes (300kgs).
If you consider that there are approx. 35 fishermen along this short stretch of coast repeating this day in day out, that’s a significant increase in the population dynamics of one species. Of course there has to be something that feeds them and keeps them going, and hence the concerns for other macro-crustacean species. Whenever I get a soft lobster in a pot, if velvets have got into the pot, the soft lobster is doomed, similarly with a soft edible (brown) crab; shore crabs are nothing more than an easy small snack.
In the central North Sea (which is predominantly where we are) lobsters, edible crabs etc. used to have a specific moulting period, once it was over that was it, last year I had soft lobsters in December, and edible crabs were soft from April through to December, not the short couple of months that was the normal range for moulting. Velvets have usually \'turned in\' around August, this year it appeared to be all over in a few week back end of July. I know this probably sounds crazy, but perhaps they have subconsciously realised that to moult over a long period of time in conjunction with the moulting period of other species increases their vulnerability and reduces their own feeding opportunities. Better to reduce the risk and increase the feeding potential, there are many instances in nature where a superabundant population can very quickly adapt to its environment, due to the driver of intra-species competition.
So if you caught 10 cod over a three day period (outside the normal range of historical catches), it is entirely plausible that this coincided with an abundant food supply, but one which also coincided with a lack of velvet crabs due to them hiding away during the moulting phase (reduced predation on other crustacean species, at the same time being vulnerable themselves). Once they had \'turned out\' (hardened), they become the principal predator, leaving minimal food for other predatory species. I guess a good analogy would be locusts or soldier ants in a jungle; after all they are from the same group of animals (Arthropods).
As Chris quite rightly says, some species are particularly susceptible to cold winters and following such, may take many years to recover, Wrasse and conger are classic examples of this, so are 0-gp bass (1st yr fish). So it is entirely feasible that given reduced competition for food and a slight increase in sea temperature that the wrasse would begin to re-establish itself.
As I said in my first post, I think the key is competition for food, but not just at the top of the food chain, there may well be shifts in apex predators in each key trophic level. In discussions with shell fishermen this year I\'ve heard rumblings that the edible crab catches are down on previous years and this would appear to be borne out in my own catch data (of course the same old phrase surfaces as well \" we never thought the edibles could be fished out!!!!!!\", where have I heard that before).
Rob Adair also makes an interesting point in that “we should be seeing other warm water species moving in\". His example of the Rays bream is an interesting point. My old club Reckitts SAC (Hull), used to run the Withernsea Open, formerly the Feedex and Shakespeare Open (one of the (if not the biggest) matches on the winter open circuit), within the rules, there is a specific a rule that states \' no Rays Bream can be weighed in\'. This is because during November annually large numbers of Rays bream were washed up on the shoreline dead and anglers (unscrupulous) were weighing them in.
These fish migrate into the North Sea during late summer on the Gulf Stream currents and as summer recedes they get caught in cold water currents and cannot survive, hence the rule to prevent cheating. What is more to the point is that during the late 70\'s and early 80\'s when this occurred they were extremely abundant, I haven\'t seen one for 20 years at least, and this event occurred when there was a last significant negative phase of the North Atlantic Oscillation!!!!!.
With regard to a potential lack of summer species, well its not really the case, Red mullet are present in the North Sea in such numbers that there is now a dedicated fishery for them, I\'ve caught them in the Humber Estuary!!!! You only need to look at the bass, 35 to 6lb in a session off the Yorkshire coast, best I\'ve heard of was 42 to a shore angler!!!!!!! We\'ve had 0-gp bass in the Humber estuary and spawning fish along the coast, they are breeding in Yorkshire. The Pollack are definitely on the increase, with bigger and better fish caught each year. There however, more subtle changes, Tope, a species that’s distribution definitely linked to water temperature is present for longer periods than was the case even a few years ago. When we first started to target them it was not until the last week in July before we picked them up, we now see them in early June. The smoothhound are on the increase, with fish to 16lbs being recorded and up to 23 smuts in a session.
So despite the decline in the good old cod, what have we got to look forward to, well this species list is encouraging; Tope, Bass, Pollock, smoothhound and even red mullet if your inclined to specialist fishing.!!!!!!
Cheers
Doc
The data clearly show that off the east Yorkshire coast 10 years ago you could count on the fingers of one hand the number of velvet crab caught by a single fisherman per year (4 or 5), presently I\'m averaging between 5 or 6 per pot, and based on 6 fleets (20 pots per fleet) I can catch 100kgs per day and on a good day 10 boxes (300kgs).
If you consider that there are approx. 35 fishermen along this short stretch of coast repeating this day in day out, that’s a significant increase in the population dynamics of one species. Of course there has to be something that feeds them and keeps them going, and hence the concerns for other macro-crustacean species. Whenever I get a soft lobster in a pot, if velvets have got into the pot, the soft lobster is doomed, similarly with a soft edible (brown) crab; shore crabs are nothing more than an easy small snack.
In the central North Sea (which is predominantly where we are) lobsters, edible crabs etc. used to have a specific moulting period, once it was over that was it, last year I had soft lobsters in December, and edible crabs were soft from April through to December, not the short couple of months that was the normal range for moulting. Velvets have usually \'turned in\' around August, this year it appeared to be all over in a few week back end of July. I know this probably sounds crazy, but perhaps they have subconsciously realised that to moult over a long period of time in conjunction with the moulting period of other species increases their vulnerability and reduces their own feeding opportunities. Better to reduce the risk and increase the feeding potential, there are many instances in nature where a superabundant population can very quickly adapt to its environment, due to the driver of intra-species competition.
So if you caught 10 cod over a three day period (outside the normal range of historical catches), it is entirely plausible that this coincided with an abundant food supply, but one which also coincided with a lack of velvet crabs due to them hiding away during the moulting phase (reduced predation on other crustacean species, at the same time being vulnerable themselves). Once they had \'turned out\' (hardened), they become the principal predator, leaving minimal food for other predatory species. I guess a good analogy would be locusts or soldier ants in a jungle; after all they are from the same group of animals (Arthropods).
As Chris quite rightly says, some species are particularly susceptible to cold winters and following such, may take many years to recover, Wrasse and conger are classic examples of this, so are 0-gp bass (1st yr fish). So it is entirely feasible that given reduced competition for food and a slight increase in sea temperature that the wrasse would begin to re-establish itself.
As I said in my first post, I think the key is competition for food, but not just at the top of the food chain, there may well be shifts in apex predators in each key trophic level. In discussions with shell fishermen this year I\'ve heard rumblings that the edible crab catches are down on previous years and this would appear to be borne out in my own catch data (of course the same old phrase surfaces as well \" we never thought the edibles could be fished out!!!!!!\", where have I heard that before).
Rob Adair also makes an interesting point in that “we should be seeing other warm water species moving in\". His example of the Rays bream is an interesting point. My old club Reckitts SAC (Hull), used to run the Withernsea Open, formerly the Feedex and Shakespeare Open (one of the (if not the biggest) matches on the winter open circuit), within the rules, there is a specific a rule that states \' no Rays Bream can be weighed in\'. This is because during November annually large numbers of Rays bream were washed up on the shoreline dead and anglers (unscrupulous) were weighing them in.
These fish migrate into the North Sea during late summer on the Gulf Stream currents and as summer recedes they get caught in cold water currents and cannot survive, hence the rule to prevent cheating. What is more to the point is that during the late 70\'s and early 80\'s when this occurred they were extremely abundant, I haven\'t seen one for 20 years at least, and this event occurred when there was a last significant negative phase of the North Atlantic Oscillation!!!!!.
With regard to a potential lack of summer species, well its not really the case, Red mullet are present in the North Sea in such numbers that there is now a dedicated fishery for them, I\'ve caught them in the Humber Estuary!!!! You only need to look at the bass, 35 to 6lb in a session off the Yorkshire coast, best I\'ve heard of was 42 to a shore angler!!!!!!! We\'ve had 0-gp bass in the Humber estuary and spawning fish along the coast, they are breeding in Yorkshire. The Pollack are definitely on the increase, with bigger and better fish caught each year. There however, more subtle changes, Tope, a species that’s distribution definitely linked to water temperature is present for longer periods than was the case even a few years ago. When we first started to target them it was not until the last week in July before we picked them up, we now see them in early June. The smoothhound are on the increase, with fish to 16lbs being recorded and up to 23 smuts in a session.
So despite the decline in the good old cod, what have we got to look forward to, well this species list is encouraging; Tope, Bass, Pollock, smoothhound and even red mullet if your inclined to specialist fishing.!!!!!!
Cheers
Doc
