A Fish Descending Device (FDD), also known as a fish descender, is a tool used to safely release fish caught in deep water, particularly species suffering from barotrauma (pressure-related injuries). These devices help return fish to their natural depth, increasing survival rates by allowing them to recompress and recover.
Types of Fish Descenders:
1. Inverted Hook Devices (e.g., Shelton Fish Descender, SeaQualizer)
– A weighted hook or clamp holds the fish’s lip and rapidly lowers it to depth.
– Releases automatically when reaching the target depth.
2. Barbless Weighted Tools (e.g., Descending Weights, Fish Saver)
– A barbless hook or clamp attaches to the fish, with a weight to help it sink.
– The fish shakes free once pressure normalizes.
3. Release Baskets/Cages (e.g., RokLees Fish Descender)
– A cage holds the fish while lowering it; it opens at depth.
4. Venting Tools (Alternative Method)
– A needle deflates the swim bladder to relieve pressure (controversial; descending is often preferred).
Why Use a Fish Descender?
– Barotrauma Prevention: Deep-water fish (e.g., snapper, grouper, rockfish) often suffer swim bladder expansion when rapidly brought to the surface.
– Improved Survival: Studies show fish returned to depth have higher survival rates than vented or surface-released fish.
– Regulatory Compliance: Some fisheries require descenders for catch-and-release fishing.
How to Use a Fish Descender:
1. Attach the device to the fish’s jaw or lip.
2. Lower the fish quickly to its capture depth (or at least 30–60 feet).
3. Release – Most devices automatically detach or allow the fish to swim away.
Best Practices:
– Minimize handling time.
– Use non-stainless steel hooks for faster degradation if the fish isn’t retrieved.
– Avoid venting unless necessary (descending is often safer).
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