Catching And Releasing

[Guest danielinbyron]

Just thought I'd share this ... the reply was to the question as to releasing bream and blackfish and pigs and wether it was best to use a rag? And the effect on the fishes coat.... I noticed in bashirs "pig photos" the old rag hangin out the shorts.

Great question,

The marine biologist wasn’t talking about oil, but the slime coat which covers the fishes scales. The slime coat is composed of a very thin layer of mucopolysaccharides formed from epithelial and mucous cells in the fishes skin. This thin layer contains various specific and non specific immune substances which form part of the fishes defence system against infection. The slime coat is constantly being sloughed off and replaced and in doing so it constantly removes micro organisms from the fishes skin and also protects it from osmotic imbalances. In other words, the slime layer of fish is a living barrier between the fish and its surrounding environment. When its damaged or disrupted, there is a chance of the fish developing infection and other problems, particularly in situations where the fish is stressed or compromised and the water quality is poor.

In my opinion as a professional fish pathologist, using rags , even wet rags, is more detrimental than wet hands when handling fish. The problem with rags is they provide you with more grip, which means using a rag actually removes more slime from the fish than if you use bare hands. The advantages of rags are that they cushion the fish from hard objects, you’re less likely to drop them and damage them that way, and the rag provides a cool moist surface. A wet rag is certainly better than any dry, hot surface, including dry hands. However, I put wet hands above a wet rag in the fish friendliness stakes, and as you pointed out, the best situation for any fish to provide the best protection of the slime coat is not to handle it at all.

Studies of the mortality of fish captured and released by recreational anglers indicate that there are many factors influencing the survival outcomes of the released fish. The main variables directly affecting immediate survival include the species and size of fish captured, anatomical hooking location, depth of capture, water temperature, and the time required for playing and handling. In general the survival rates of fishes released by recreational fishers are very high, approaching 100% when the fish are hooked in the mouth or lip, played quickly and handled with care. However it is also recognised that there are some sublethal effects associated with catch and release fishing, one being infection of injuries sustained during capture and handling. Because of this, best practice handling techniques which protect the fishes slime coat should be used wherever possible to improve the survival chances of fish during catch and release fishing.

Some good information on this subject is now available from the National Strategy for the Survival of Released Line Caught Fish (for details see

HYPERLINK "http://www.info-fish.net/releasefish/econtent.asp?lang=1&id=82" www.info-fish.net/releasefish/econtent.asp?lang=1&id=82 - and go to the “releasing species” section for great fact sheets on how to release a range of species from bream to billfish). A great generic pamphlet on proper handling of fish can also be found at HYPERLINK "http://www.fishsa.com/SARFAC-HandlingFish.pdf" www.fishsa.com/SARFAC-HandlingFish.pdf .

Ben Diggles

Edited November 6, 2006 by danielinbyron

[Davemmm]

The marine biologist wasn’t talking about oil, but the slime coat which covers the fishes scales. The slime coat is composed of a very thin layer of mucopolysaccharides formed from epithelial and mucous cells in the fishes skin. This thin layer contains various specific and non specific immune substances which form part of the fishes defence system against infection.

This explains why wiping the slime from a flatty on to place where it has spiked you stops it from hurting.