One year after DH oil spill, fish as bioindicators

[MathGeek]

The picture above is my sons and I with a big drum. During our trip to Louisiana last year, Joshua (younger son) collected data for his science fair project, "Condition Indexes of Fish as Bioindicators One Year After the Deepwater Horizon Oil Spill." Joshua weighed and measured over 500 fish in the Lafourche and Calcasieu areas and compared the actual fish weights with the expected weights (long term Louisiana averages) to determine the impact of the oil spill in the Lafourche area and the impact of increased oystering, crabbing, and shrimping pressure in the Calcasieu area.

Joshua's science fair project won Grand Champion at his school, Grand Champion at the Pikes Peak Regional Science fair, and first place in Environmental Sciences at the Colorado State Science Fair. His mother and I are very proud of him. He is an avid fisherman and aspiring fisheries scientist.

[MathGeek]

The above figure was the summary of Joshua's results. Note that the thinnest fish on average were Black Drum in Calcasieu. Joshua concluded that the increased oystering in Calcasieu is having a more negative impact than the loss of oysters in the Lafourche area due to the oil spill. Since the Black Drum's food supply in Calcasieu has been greatly reduced, the fish are much thinner than the long term Louisiana average. Harvesting all the Black Drum you catch will both help the oysters recover more quickly and also leave more food for the remaining Black Drum. It will also leave more food for the redfish, as in the absence of oysters, Black Drum eat a lot more crabs and are a much stronger food competitor with the redfish.

Also note that the redfish and spotted seatrout are also thinner than expected in Calcasieu. This suggests that relative to the abundance of redfish and spotted seatrout, there is less to eat than the long term Louisiana average.

[southern151]

And, how old is this young man?

Very impressive report! Well thought out and, impressive study!

[Duck Butter]

Wow, I know biology majors that couldn't produce that graph! Congratulations

[jgannard]

Congrates, little man

[saltysully]

Great work and very interesting!!!

[skinman]

Impressive for sure! Congrats to you both!

[jdm4x43732]

Pretty interesting stuff.

[mcjaredsandwich]

Thats awesome!! Congrats to him, and you must be proud. Hes got a good future ahead of him.

[Salty]

He makes more "cents" than the biologists we have now.

Congrats!

[Ray]

We have less Drum than Reds in Big Lake. Cause cents the last couple years, Drum have become our new Trophy Fish. So many more people are targeting them.

[MathGeek]

Originally Posted by Ray

We have less Drum than Reds in Big Lake. Cause cents the last couple years, Drum have become our new Trophy Fish. So many more people are targeting them.

There are probably fewer drum because of a combination of starving to death and migrating elsewhere to find food. Drum need several oysters each day to maintain body condition. According to my son's background work, most fish are in danger of dying when their body condition drops below 80% of the expected weight, and a lot of the drum he measured from Calcasieu had body condition between 80% and 90%. (Red Xs in the above graph.)

It is a paradox that the best thing to do for a species in decline is to harvest more of them, but it's a common situation in wildlife management. If there are too many deer relative to the available forage, the best solution is for hunters to harvest the surplus above what can be sustained on the available forage. Protecting their food source is key in protecting any species of wildlife. The oysters need to be protected until their numbers return to sustainable levels, and an important part of protecting the oysters is reducing the numbers of their primary prey species, which is black drum.

[Ray]

I heard from a very good source that the La. Legislature is looking at reinstating Tonging in Calcasieu Lake. Some Oyster fishermen are happy about it, some are not.

I was just jerking your chain about the Drum. Everyone was posting pictures of their Trophy Drum last year, check out my profile picture.

Thinking about having a Drum Tournament in late Aug. or early Sept. That sould bring out the real fishermen. T-Tops, Aluminum Boats and Live Bait will be allowed. We can thin out a few of them big nasty trophys.