# The Naked Scientists Forum

### Author Topic: Solving the problem of fish stocks.....  (Read 30603 times)

#### Andrew K Fletcher

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##### Solving the problem of fish stocks.....
« Reply #50 on: 15/06/2008 16:26:23 »
Your idea of releasing the eggs so that we have a higher rate of return to the ocean is a good one. Fish normally release their eggs and yes they often become cannibals and eat both the eggs and the emerging young, so releasing the fertilized eggs where the sonar does not show huge shoals of fish is always going to be a wise move, and lets face it the fishermen are struggling to find fish these days. A good friend of mine runs a very expensive boat out from Brixham and several times has returned back to port after a week without enough fish to pay his crews wages. So I guess if the eggs all get eaten we don’t have a problem with dwindling fish stocks to begin with.

Another alternative is that the eggs are nurtured until they hatch and then release them to feed on the plankton in stages rather than putting them all out in one place. The collecting team might prove difficult given the huge distances these fishermen travel in order to locate catches. However having an official on board might prove to be more cost effective than sending out a boat and a team.

There is another option and that is a holding tank secured to take the eggs and milt from the fish on landing them back at port, this could be a percentage of the roe in exchange for letting the fisherman keep the whole catch rather than dumping them overboard.

#### sooyeah

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##### Solving the problem of fish stocks.....
« Reply #51 on: 15/06/2008 17:00:53 »
Your idea of releasing the eggs so that we have a higher rate of return to the ocean is a good one. Fish normally release their eggs and yes they often become cannibals and eat both the eggs and the emerging young, so releasing the fertilized eggs where the sonar does not show huge shoals of fish is always going to be a wise move, and lets face it the fishermen are struggling to find fish these days.

I would extend it further then just dropping the eggs away from big shoals of fish. I am also thinking about and considering, the best place in the sea for them to hatch, are they better in shallow water? what do they need to feed on? Where do the parent fish normally release them? These are the types of questions I would consider; To maximise survival rates.

A good friend of mine runs a very expensive boat out from Brixham and several times has returned back to port after a week without enough fish to pay his crews wages. So I guess if the eggs all get eaten we don’t have a problem with dwindling fish stocks to begin with.

The above solution is a way of improving the situation, it will help keep the fish going. But it is not the answer.

Another alternative is that the eggs are nurtured until they hatch and then release them to feed on the plankton in stages rather than putting them all out in one place. The collecting team might prove difficult given the huge distances these fishermen travel in order to locate catches. However having an official on board might prove to be more cost effective than sending out a boat and a team.

hatching the eggs it's the same idea already discussed before. Wait, actually you could have a nursery on board ship. So in between trips eggs could hatch and then on your way out for the next trip, you could release them. There's another solution, the fisher men could release some eggs but also hold back others to hatch, and then release the hatchlings on there next trip out.

There is another option and that is a holding tank secured to take the eggs and milt from the fish on landing them back at port, this could be a percentage of the roe in exchange for letting the fisherman keep the whole catch rather than dumping them overboard.

A fertilised fish egg Tax, not bad. Then the eggs could be moved to holding areas and then released as required by a specialist team. Each country would have and fund it's own group.

#### Andrew K Fletcher

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##### Solving the problem of fish stocks.....
« Reply #52 on: 15/06/2008 17:29:32 »
When cod spawn
Every December and January, sexually mature Northeast Arctic cod migrate from the Barents Sea to their spawning grounds between Finnmark and western Norway. The most important of these grounds are in Lofoten and Vesterålen.

By Beate Hoddevik Sunnset
The lifecycle of the cod is certainly interesting and there are contact numbers on this site to ask if we could have someone add their expertise and thoughts in this area of research to the possiblity of replenishing fish stocks. Might be worth dropping them a line?
http://www.imr.no/english/news/2007/when_cod_spawn

#### sooyeah

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##### Solving the problem of fish stocks.....
« Reply #53 on: 15/06/2008 17:37:27 »
When cod spawn
Every December and January, sexually mature Northeast Arctic cod migrate from the Barents Sea to their spawning grounds between Finnmark and western Norway. The most important of these grounds are in Lofoten and Vesterålen.

By Beate Hoddevik Sunnset
The lifecycle of the cod is certainly interesting and there are contact numbers on this site to ask if we could have someone add their expertise and thoughts in this area of research to the possiblity of replenishing fish stocks. Might be worth dropping them a line?
http://www.imr.no/english/news/2007/when_cod_spawn

Couldn't we just email the link to this thread? Pretty much it's all here.

I will reread the whole thread at some point, sure I'll spot something I missed.

It's crazy what a few people can do when they bounce ideas about.

#### Andrew K Fletcher

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##### Solving the problem of fish stocks.....
« Reply #54 on: 15/06/2008 17:54:14 »
Sounds good to me and we now have some proof that it will work :) Read on

Newfoundland Fish Hatchery

The hatching of cod fish from the ova of the female fish has not been common practice in the history of the cod fishery. However, a not too well known hatchery was established in Newfoundland in 1890 which operated for seven years and released over a billion cod fry into the waters of coastal Newfoundland.

During the 1800s the cod fishery in Newfoundland realized many difficult years when either catches were low or markets were poor. Since the health of the Newfoundland economy went hand in hand with the success of the cod fishery, the Government of the day decided to explore possibilities for improvements. There was no Dept. of Fisheries so in 1887 the Govovernment decided to establish a fisheries Commission to explore the issues and make recommendations for improvements.

Site of the Fish Hatchery of the 1890s

The Commission soon focussed on the possibility of hatching cod fish to improve catches. They were aware of operations in the US and Norway and felt that it held possibilities for the waters of Newfoundland. It so happened that a group from Norway arrived in Newfoundland later in 1887 to study the cod fishery so the Commission was anxious to examine the local fishery and report back on their conclusions regarding the fishing industry in Newfoundland. Adolph Nielson, a member the group who submitted the subsequent report, impressed the members of the Commission such that a proposal was sent to him to take on the position of Supt of Fisheries for Newfoundland and he accepted the assignment for \$3000 per year.

Nielson arrived in Newfoundland in February 1889 to take on his new position and lost no time getting started with his new responsibilities. By the middle of July 1889 he had a hatchery completed and ready for the hatching of cod fish. His plan was to obtain mature fish from local fishermen and transport them to the hatchery in covered wooden containers with plenty of holes to permit a continuous supply of sea water as the containers were towed to the hatchery by a steam powered vessel. The fish would then be placed in breeding tanks that were continuously supplied with fresh sea water and where the females would lay their eggs to be fertilized by the male fish. The fertilized ova would float to the surface of the water to be removed and placed in special tanks in the laboratory located inside the hatchery building.

An 1890s Photo of the Fish Hatchery

Unfortunately, the female cod fish had laid their eggs before the middle of July so nothing was achieved in 1889.

In the spring of 1890 Nielson and his team-were ready. The required mature cod fish were delivered to the site and the intricate hatching process proceeded for about three months when the developed fish fry were transported to various areas of Trinity, Conception, and Fortune Bays where they were released. The hatch rate of the ova improved from 50% in the first year to 75% in the seventh year.

Local fishermen reported finding large numbers of juvenile cod-fish in the bays during the following years but critics claimed that the hatching process was no better than the natural process. The Government that supported the hatchery was voted out of office and the new government did not support the operation so there are no reported results beyond 1896. By that time over 186 million cod fry were hatched and released.

Nielsen had many other projects other than the hatching of cod fish which was a seasonal operation occupying about three months of the year. A popular project that he spear headed concerned the preservation of lobster ova. He developed a floating incubator that could be used after minimal training to permit the hatching of lobster fry from the ova that would be otherwise cooked with the rest of the lobster.

Around the coast of Newfoundland lobster canning factories were common during the 1890s. These operations were not concerned with preserving the lobster population so female lobsters were thrown in the cooking vats with the ova attached. This meant a great loss to the growth of the lobster population especially since the ova was already fertilized.

Seventeen of the floating incubators were located where Fisheries personnel removed the ova and attended to the incubation process. In 1895 over 174 million lobster fry were hatched and released. People involved in the canning process eventually realized the potential of the process and got on the lobster preservation band wagon resulting in the hatching of billions of lobsters.
http://www.newfoundland-books.com/site/1495114/page/912775

http://icesjms.oxfordjournals.org/cgi/content/full/63/7/1353  Salmon in Japan
« Last Edit: 15/06/2008 18:20:40 by Andrew K Fletcher »

#### sooyeah

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##### Solving the problem of fish stocks.....
« Reply #55 on: 15/06/2008 18:54:51 »

http://www.newfoundland-books.com/site/1495114/page/912775

So that finished when they were voted out, but even so 174,000,000 fry, isn't a small number and that's one year.

http://icesjms.oxfordjournals.org/cgi/content/full/63/7/1353  Salmon in Japan

Quote
Taken from the above article...

To use these programmes more effectively, it is necessary to evaluate both their river- and species-specific benefits and compare hatchery programmes with other management tools, such as fishery controls and habitat rehabilitation. Future hatchery programmes should incorporate active, adaptive learning approaches to minimize the risks associated with artificial propagation and to promote sustainable salmon stocks.

and

In Japan, considerable effort has been made to increase the number and survival of hatchery-reared fish (Nogawa and Yagisawa, 1994; Seki and Shimizu, 1996), most results being published in the grey literature. Japanese hatchery technology is well-developed, and both the quality and quantity of juveniles released are high because of the substantial efforts of hatchery managers. Japanese chum salmon are considered to be representative of the phenomenal success of hatchery programmes, which are seen as necessary to sustaining catches of Pacific salmon in Hokkaido. Unfortunately, there have been few efforts to assess whether these programmes have actually increased the population of the target species after accounting for the negative impact on wild fish and environmental changes. In particular, there have been few river-specific evaluations of their effectiveness. There are risks associated with hatchery programmes, such as competition between cultured and wild salmon, genetic impacts on wild salmon, domestication selection, and disease outbreaks (National Research Council, 1996; Altukhov et al., 2000). Overall they may be replacing wild salmon rather than augmenting total salmon production (Nickelson et al., 1986; Hilborn and Eggers, 2000; Sweeting et al., 2003). In addition, if genetically modified captive stock is released into rivers where wild fish occur, both wild and hatchery fish may decline (Muir and Howard, 1999; Devlin et al., 2004). For the sustainable use of salmon resources, it is necessary, therefore, to consider not only the potential benefits but also the risks, associated with hatchery programmes. We suggest adopting the concept of managing hatchery and wild fish together (Fisheries Agency of Japan, 2004).

To use hatchery programmes more effectively, we need to evaluate their river- and species-specific benefits first (cf. Nickelson et al., 1986; Hyatt et al., 2005), and then compare hatchery programmes with other management tools. The latter should include spawning-bed enhancement (Merz et al., 2004), rehabilitation of channelized streams (Nagata et al., 2002), and improvements to access for migratory fish (Sagawa et al., 2004), but fisheries management should be implemented more actively. Such conservation management tools will guarantee the long-term sustainability of salmon stocks. Future hatchery programmes should clarify goals and incorporate active, adaptive learning approaches to minimize the risks associated with them and promote the sustainable use of salmon stocks. Scientists in Japan have initiated a dialogue about the most appropriate future direction for Pacific salmon hatchery programmes, with special reference to wild salmon.

So it's been done and being done, so the real question is:

What is the best option to help promote a truly healthly sea?

So I suppose the first question is: what is a truly healthy sea? Another_someone did also ask this; that's I think where we should start.

going to start looking here- http://www.seaweb.org/home.php

and here- http://www.healthyocean.com/solutions.html
« Last Edit: 15/06/2008 19:26:10 by JOLLY »

#### lyner

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##### Solving the problem of fish stocks.....
« Reply #56 on: 19/08/2009 09:21:18 »
It strikes me that it's the harversting process that needs control rather than the spawning process. The present system is abused because of the quota system. Vast amounts of fish are dumped because of the regulations. Why ? If the fish have been caught they should be eaten. A system of regs which promotes this behaviour is clearly flawed.

Juvenile fish don't reproduce so increasing net mesh size isn't going to have a significant effect on the spawning rate. There absolutely have to be totally protected areas of all kinds of seabed where populations can get to natural levels.
This must involve very 'big stick' policing.
The area of continental shelf is huge and the potential for gathering the energy arriving from the Sun is moe than humans will need, possibly ever. The situation is totally loony at the moment. It's the equivalent of cattle rustling made legal.

#### Andrew K Fletcher

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##### Solving the problem of fish stocks.....
« Reply #57 on: 01/09/2009 18:58:19 »
Agreed. But how do the fish that need protecting know that the area is safe and this approach cannot protect migratory species, which is the whole point of the salmon breeding programme.

Returning hatchlings from fertilized eggs taken from fish that are harvested has to be a great policy.

#### lyner

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##### Solving the problem of fish stocks.....
« Reply #58 on: 02/09/2009 18:34:08 »
I saw a TV prog about that. It did concern me that there is a risk of many weaker individuals being saved and returned to the population - thus weakening the species.
The rivers, in the case of salmon are the equivalent to the safe areas and could have tighter quotas imposed, possibly imposing an embargo on a particular river once every five(?) years.
The fish don't have to 'know' that the area is safe. There will just be more mature adults there and they just have to get on with breeding in peace whilst they're there. ('There there'?) Your point does, however, raise the question of how big the go / no-go areas might need to be. Chichester Harbour is a spawning ground and is protected against net and live bait rod fishing. It's teeming with Sea Bass.

#### Andrew K Fletcher

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##### Solving the problem of fish stocks.....
« Reply #59 on: 12/09/2009 11:33:23 »
Salmon and seabass and sea trout could as you say benefit greatly from a few years of restrictions in the rivers and around the entrances to the rivers. I still see netting done around the coast very close to shore and know it is illegal, but the fishermen are having a tough time as it is.

The most productive areas for fishing however are in the North Sea and I still feel that returning fry to the ocean should not be ignored and could greatly improve the fish stocks without disrupting the fishing further.

Hope someone will get their head around the simplicity of milking fish and stripping them of roe, hatching the fry and pouring them back into the ocean rather than eating all of the roe

#### yor_on

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##### Solving the problem of fish stocks.....
« Reply #60 on: 09/03/2010 21:13:05 »

Right the government or an N.G.O, builds fish farms to restock the sea with missing species. So each country would have one. Right, therefore the fish would be owned by either the 'people' or greenpeace for example. So any fisher men would have to pay the government for each fish they caught. Right so that would keep fish stocks up, help enforcement of legal restrictions, and generate revenue for preservation of the sea. You may have to tag the fish but it would surely help.

Kind'a'luv'it.

We should DNA-mark the whole planet. Carrying small markers identifying all things there is. Perhaps also with 'green stamps' for those most environmentally correct. And as we explore Space? We could do the same there? and then devise systems to even out distribution etc.

What a collection we might get, and then we could . .

Nobody thought of trying to limit ourselves instead, giving our little planet some well deserved rest, and a little space to recover? I'm betting on nature being much more adaptive and effective than all our 'stock takings' taken together, and guaranteed saner too.

#### The Naked Scientists Forum

##### Solving the problem of fish stocks.....
« Reply #60 on: 09/03/2010 21:13:05 »