Playback Rate 1

Timecode: 00:00:00

RedSnapper_ShrimpBycatch&NaturalMortality_Gallaway_Benny_BryanTX_25August2022_Reel4125.mp3

Benny Gallaway [00:00:00] I think the whole "we've got to manage shrimp trawl bycatch to have a fishery" started with the 1995 stock assessment, which basically came up with a strategy that required shrimp bycatch mortality of juvenile red snapper to be reduced by 50%.

Benny Gallaway [00:00:21] And, and, shortly thereafter, federal regulations mandated the use of specific bycatch reduction devices to do that. They had been tested, and they had been tested in a way where you'd have a net with a bycatch reduction device and if it's okay, I'll call those "BRDs", B, R, D, S, in one net, and without a BRD in the other net. And sure enough, you would reduce the number of juvenile red snapper you'd put on the deck by a large amount.

Benny Gallaway [00:00:55] The problem is, if you observe the escapement of those fish, it's at the end of the tow, when the net is being retrieved. It's more like the fish are being burped out at the end of the tow. They're not continually released in a nice, healthy fashion throughout the tow.

Benny Gallaway [00:01:12] So there were some questions, "Are these things really effective or not?"

Benny Gallaway [00:01:17] And then the more we looked at it, we found out that, at that time, the natural mortality rate for these aged zero and one fish - fish in the first and second years of life - are the ones that come into the shrimp trawl bycatch, and they're called age zero and age ones.

Benny Gallaway [00:01:38] And the effectiveness of saving those from being killed by a shrimp trawl depends on how many would die naturally.

Benny Gallaway [00:01:48] We started out with the idea that the natural mortality rate was like, for relative basis, and we probably don't want to get into weeds, but for comparison, it was 0.5 and 0.1, for age zero and one, which is very low rates of natural mortality.

Benny Gallaway [00:02:05] So if you save that fish, you've got a big influx of new fish into the population as aged two and three fish.

Benny Gallaway [00:02:15] Well, it turns out, is that those aren't the natural mortality rates. The mortality rates are more like 2.0, or four times higher than what was originally estimated.

Benny Gallaway [00:02:27] So even if you save them, most of them were not going to survive to get to the directed fishery, because they were going to die from natural causes, whether or not they were caught in shrimp trawls or not...

Benny Gallaway [00:02:37] If you're a little pink fish on a mud bottom, you're going to be noticed. And there are lots of things with a mouth big enough to eat you ... sea basses, trouts, croakers, you know, the gamut, and things you might, might not think of - shrimp eels and anything with a mouth big enough to ingest a two-inch fish, which is basically a lot of things out there.

Benny Gallaway [00:03:04] So, so if you're banking on that influx of fish, you're in bad shape.