Round Gobies Ecosystem Damage and Sport Fishing

Round Gobies (Neogobius melanostomus (Pallas)  , Ecosystem Damage, and  Sport Fishing

Saturday October 2nd 2010

Goby Fish

On Monday June 29th, 2,010 Ontario Sport-fishing posted a fisherman’s comment.  He said, “ I used  the goby fish head for bait, and ahuge Perch was all over it. Big catfish eat them. And, I got a huge Silver Bass on parts of a goby.” Therefore, it appears that the local fish are used to goby fish, and use them as food fish. Environmental Canada news release of July 23, 1999 stated the round goby fed on 78 zebra mussels a day.  But, as this fisherman said on June 29th,  2,010 the gobies are in turn preyed upon by several sport fish species: brown trout, small-mouth bass, walleye, sturgeon and yellow perch. Gobies are a menace to native fish populations by eating their eggs and offspring.  Gobies are aggressive in competing for food and deny other fish to spawning grounds.  Currently Hamilton Harbour has both salmon and trout heading for spawning grounds.  And, the goby fish will chase a fish twice its size.  Sport fishermen find goby fish not only invasive, but a nuisance as they steal the bait of their fishing lines. Today, October 1st, 2,010 Doug caught a goby fish in Hamilton Harbour and the size of its mouth looks like it is ready to devour anything in sight.

Boat Fisherman and gulls
A most interesting study has just been published in Eco-toxicology and Environmental Safety for Oct. 2,010. Among other researchers, is Dr. Signal Balshine, Dept. Psychology, Neuroscience and Behaviour at McMaster University.  These researchers  investigate the question “Signatures of contamination in invasive round gobies (Neogobins melanostomas): A double strke for ecosystem health ?”  These researchers state “The invasive round goby has a recognized role in transferring contaminants through food webs, but little has been done on the contamnant impact on round gobies themselves.  Their study found (1) Copper and Cadmium, elevated in livers of fish from contaminantes.  (2) Fish were smaller.  (3) Fish had fin loss.  (4) Males had intersex gonads and genitalia.  (5) Ehtoxyresorufin-o-deethylase (EROD) activity was higher inf fish caught near polycyotic aromatic hdrocarbon (PAH) rich sediments.  (6) And, Endrocrine disruption.  The results of this study indicate that contaminants impact the characteristics of round goby populations, which could effect  Ecosystems  beyond toxicant biomagnification. This bomagnification is – the increased concentration of a toxic chemical, at successively higher levels in a food chain.  As a result of biomagnification, organisms at the top of the food chain generally suffer greater harm from a persistent toxin or pollutant than those at lower levels.  These researchers also concluded ” this study also confrms that round gobies can be abundant in polluted habitats, which may draw predators, facilitating mobilization of contaminants in food-webs.”  Knowing about this research, leaves the question  – Are Sport Fish caught in Hamilton Harbour safe to eat?” Doug Worrall Says  “Some people do, and at there own risk, Different cultures actually eat the Carp out of Hamilton Harbour, they are not educated on the high level of Methol  Mercury and other Pollutants in the Great Lakes”.   As evironmentalists and conservationists it is imperative we educate the general public who do sport fish about food web, or, ecostudies,  in food chains.
By Jaqueline D
and
Doug Worrall