Record setting Ontario Orange-spotted Sunfish?
11-06-2012, 03:21 PM
(This post was last modified: 11-06-2012 03:26 PM by MuskieBait.)
Post: #14
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RE: Record setting Ontario Orange-spotted Sunfish?
There are two species of Crappies - White Crappie (Pomoxis anularis) and Black Crappie (Pomoxis nigromaculatus).
Aside from colouration and body pattern difference, which is often the easiest, it is often difficult to differentiate small juvenile crappie between the species since the calico patterns and the bars has not full developed. So...empirical distinguishing features are... 1) Dorsal spines - White Crappie has 5-6 dorsal spines, Black Crappie has 7-8 dorsal spines 2) Body ratio - White Crappie predorsal length (from center of pupil to origin of the first dorsal spine) is much greater than dorsal base length, Black Crappie predorsal length equals the dorsal base length, hence the body proportion of White Crappie is often longer than tall, while Black Crappie often looks more rounded. Now, going to the two picture I posted. Picture 1 - Looks like a Black Crappie in body patterning (well, a careful look and you can see the tail end of the fish is actually developing some bars). However, if you count the dorsal spines, you can count 6 (I also counted 6 on the spot). I measured the predorsal length on the picture and got Predorsal length: 4.5cm and Dorsal base: 3.7cm. Evidence suggest that this Crappie is a White Crappie. Juvenile White Crappies often do not have fully developed bars on the side of the body. However, I think this one is may be a hybrid Black x White since the lake has both. Picture 2 - Looks more like a White Crappie in body patterning...with some vertical bars developing. However, if you count the dorsal spines, you can count 7 (I also counted 7 on the spot, with the first dorsal spine very small but evident in the field and in the picture). I measured the predorsal length on the picture and got Predorsal length: 4.4cm and Dorsal base: 3.5cm. This one is clearly a hybrid since the dorsal spine count is consistent with Black Crappie but the predorsal length is consistent with White Crappie. Again, this was caught in the same lake on the same day as the fish in Picture 1. I'm not making any of this up. They are all characteristics published in research papers to clarify the identification of pure strain Black Crappies and White Crappies, and the resultant F1 and F2 hybrids that occurs in the same lake. A lot of US lakes has both species coexisting but there are clear habitat and spawning area preference between the two. My whole point is that unless you know the definitive characteristics to look for, trying to guess at something base on your memory of the appearance of the fish and pictures on internet is often very difficult to ID a species - especially when there are a few similar species occurring in the area where these species can also hybridize. I could have called Picture 1 a Black Crappie and Picture 2 a White Crappie if I had just gone by physical looks and what memory serves me, but this example just proves otherwise. To this day, I still haven't caught a pure strain White Crappie yet...gotta keep looking. Malama o ke kai Caution - Objects in picture are smaller than they appear. I am genetically predisposed to make fish look bigger. Life List: 577 species and counting (2016: 91 new species) http://muskiebaitadventures.blogspot.ca/...-list.html |
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