Another form of "bycatch" in the widest sense of the world is known as "ghost fishing". It can be defined as "...the continued capture and killing of animals by gear that has been lost or abandoned.[v]"Like other side effects of the large scale industrial exploitation of the sea ghost fishing is a relatively recent phenomenon, as in the past the fishing equipment (nets and lines) were made of biodegradable materials (rope and twine). A classic net that was lost would quickly rot away and/or sink andwhile modern equipment is made of nearly indestructible material such as nylon or other artificial materials. Ghost fishing by lost or discarded equipment include:
--> ongoing killing of target species
--> indiscriminate catching and killing of non-target species
--> damage to and killing of animals by ingesting parts of lost gear
--> potential physical damage to sea floor communities
Since the true extent of ghost fishing is not known, it increases the uncertainty of assessing the overall magnitude of the bycatch problem and hence the overfishing crisis. Within European fisheries one of themost pressing issues in this context are the gillnet fisheries in the North Atlantic which go after monkfish and deep water shark. There are convincing indications suggesting that net dumping occurs on a large scale and hence significant ghost fishing is under way [Open University, 2007]. To get a picture of the dimensions of ghost fishing, it is worthwhile to look at a calculation of Kibel et al (2007), according to which in the order of magnitude of five million crabs are caught in lost pots used as crab traps - in UK waters alone! Around 20% of the trapsare lost annually and here again the use of non-degradable material like stainless steel or plastic instead of traditional material such as woven hazel is one of the main factors. Rotting natural material also tends to be more visible (or otherwise recognizable) than the thin plastic lines of modern gear.
Fishing equipment that was lost or dumped in deep waters with insignificant currents can go on à ¬fishingà ® for years to come. In shallow waters with stronger currents and high tidal activity nets and lines tend to get entangled and are therefore are rendered more harmless in a relatively short period of time, perhaps a few months.
1.2.5 Trawling and purse seining
Without any technological adjustment trawling (including prawn/shrimp trawling) and purse seining also result in enormous amounts of unwanted bycatch. Since large scale tuna purse seining was introduced in the 1969s, large numbers of Dolphins have been killed in the process, especially since Dolphins were used as the indicator for the positions of tuna (setting on Dolphins)[vi]. The true numbers of Dolphin deaths are not known, but numbers for Pacific tuna fisheries alone vary between 137,000 for 1986 (Kibel, 2007) and over 200,000 as an upper annual estimate for the 70s (Earle, 1995)[vii].
The blindness of society, practitioners and policy makers alike is well expressed in a quote by Richard Ellis: Ã ¬It is probably no surprise to learn that the massive bycatch of spotters and spinners in the tuna purse-seine fishery has had deleterious effects on dolphin populations; it is only surprising that it took forty years to recognize that killing millions of animals in a population might permanently damage it[viii].Ã ®
2. Light at the end of the tunnel
à ¬One morning we raised forty to fifty paired Spanish draggers working Green Bank (Grand Bank area)Ã- some of them seemed to have a tailÃ-when we came over them at about 2,000 feet, we saw it was dead fish. There must have been millions of them stretching out astern of each boat that had just hauled its net and was sorting the catch on deck. Undersized fish were going over the side like confetti[ix].à ®
F. Mowat (1984) Sea of Slaughter
2.1 Coping with a Syndrome
Although the situation is dire and many fish stocks and other marine species are close to collapse, or in decline, there also are positive developments giving reason for optimism. Like all environmental issues at the interface of man and nature, the problem of overfishing and bycatch is multi-factorial - a syndrome. An effective approach has to be a combination of solutions on all levels: technological, economical, ethical and political. Every else is prone to fail. The good news is that this development appears to be under way. Some technological and behavioural advances for bycatch reduction are lined out below, sorted by fishing method:
2.1.1 Dolphin safe-tuna the first big success resulting from public pressure
We Humans tend to make a strict distinction between animals we eat and those we love, adore and sometimes keep as pets at least in Western societies. Dolphins for a long time had a positive image, partly reaching back to times of antiquity, partly resulting from popular products of the entertainment industry such as films and TV series (e.g. Flipper) or à ¬circus showsà ® in marine parks. It also is relatively easy to identify with marine mammals since they are highly developed and intelligent mammalians just as we like to see ourselves. Hence once the wider public became aware of the dolphin casualties involved in Tuna fisheries, a large public outcry was the result in many western countries. NGOs utilized the righteous emotional outrage and the call for à ¬dolphin save tunaà ®. As it happens the success came fast and Dolphin bycatch in tuna purse seining was reduced from as many as perhaps 200,000 annually to negligible levels to date. The pressure was purely based upon economic incentives: Fishermen were given Dolphin quotas which they could not exceed, and therefore killing dolphins simply would be an expensive enterprise.
--> ongoing killing of target species
--> indiscriminate catching and killing of non-target species
--> damage to and killing of animals by ingesting parts of lost gear
Since the true extent of ghost fishing is not known, it increases the uncertainty of assessing the overall magnitude of the bycatch problem and hence the overfishing crisis. Within European fisheries one of themost pressing issues in this context are the gillnet fisheries in the North Atlantic which go after monkfish and deep water shark. There are convincing indications suggesting that net dumping occurs on a large scale and hence significant ghost fishing is under way [Open University, 2007]. To get a picture of the dimensions of ghost fishing, it is worthwhile to look at a calculation of Kibel et al (2007), according to which in the order of magnitude of five million crabs are caught in lost pots used as crab traps - in UK waters alone! Around 20% of the trapsare lost annually and here again the use of non-degradable material like stainless steel or plastic instead of traditional material such as woven hazel is one of the main factors. Rotting natural material also tends to be more visible (or otherwise recognizable) than the thin plastic lines of modern gear.
Fishing equipment that was lost or dumped in deep waters with insignificant currents can go on à ¬fishingà ® for years to come. In shallow waters with stronger currents and high tidal activity nets and lines tend to get entangled and are therefore are rendered more harmless in a relatively short period of time, perhaps a few months.
1.2.5 Trawling and purse seining
Without any technological adjustment trawling (including prawn/shrimp trawling) and purse seining also result in enormous amounts of unwanted bycatch. Since large scale tuna purse seining was introduced in the 1969s, large numbers of Dolphins have been killed in the process, especially since Dolphins were used as the indicator for the positions of tuna (setting on Dolphins)[vi]. The true numbers of Dolphin deaths are not known, but numbers for Pacific tuna fisheries alone vary between 137,000 for 1986 (Kibel, 2007) and over 200,000 as an upper annual estimate for the 70s (Earle, 1995)[vii].
The blindness of society, practitioners and policy makers alike is well expressed in a quote by Richard Ellis: Ã ¬It is probably no surprise to learn that the massive bycatch of spotters and spinners in the tuna purse-seine fishery has had deleterious effects on dolphin populations; it is only surprising that it took forty years to recognize that killing millions of animals in a population might permanently damage it[viii].Ã ®
2. Light at the end of the tunnel
à ¬One morning we raised forty to fifty paired Spanish draggers working Green Bank (Grand Bank area)Ã- some of them seemed to have a tailÃ-when we came over them at about 2,000 feet, we saw it was dead fish. There must have been millions of them stretching out astern of each boat that had just hauled its net and was sorting the catch on deck. Undersized fish were going over the side like confetti[ix].à ®
F. Mowat (1984) Sea of Slaughter
2.1 Coping with a Syndrome
Although the situation is dire and many fish stocks and other marine species are close to collapse, or in decline, there also are positive developments giving reason for optimism. Like all environmental issues at the interface of man and nature, the problem of overfishing and bycatch is multi-factorial - a syndrome. An effective approach has to be a combination of solutions on all levels: technological, economical, ethical and political. Every else is prone to fail. The good news is that this development appears to be under way. Some technological and behavioural advances for bycatch reduction are lined out below, sorted by fishing method:
2.1.1 Dolphin safe-tuna the first big success resulting from public pressure
We Humans tend to make a strict distinction between animals we eat and those we love, adore and sometimes keep as pets at least in Western societies. Dolphins for a long time had a positive image, partly reaching back to times of antiquity, partly resulting from popular products of the entertainment industry such as films and TV series (e.g. Flipper) or à ¬circus showsà ® in marine parks. It also is relatively easy to identify with marine mammals since they are highly developed and intelligent mammalians just as we like to see ourselves. Hence once the wider public became aware of the dolphin casualties involved in Tuna fisheries, a large public outcry was the result in many western countries. NGOs utilized the righteous emotional outrage and the call for à ¬dolphin save tunaà ®. As it happens the success came fast and Dolphin bycatch in tuna purse seining was reduced from as many as perhaps 200,000 annually to negligible levels to date. The pressure was purely based upon economic incentives: Fishermen were given Dolphin quotas which they could not exceed, and therefore killing dolphins simply would be an expensive enterprise.
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