In yesterday’s post we highlighted some of the results from our fourth, and most recent, sampling event. In today’s post, we will be talking about what we caught in the event prior.
The third sampling event took place from March 29th to April 2nd. No river herring were caught; however, we did catch a number of large common carp (Cyprinus carpio), each weighing around 10 to 11 lbs. Common carp are not native to NJ, or to the United States for that matter. They were first introduced to North American in 1831 by Captain Henry Robinson of New York who brought them over from France. In a little over 50 years, common carp had become established in waterbodies throughout the nation. In New Jersey, common carp are present in almost every lake, pond, river, or stream. They have a long lifespan, living anywhere from 12 to 20 years. They forage on the bottom sediments of waterbodies, using their fleshy barbels to taste for insects and other invertebrates. Yet they are largely non-discriminant eaters, often consuming vegetable matter in addition to insects (NJDEP).
In addition to the common carp, we also caught one mirror carp (Cyprinus carpio carpio). The mirror carp is a variant of the common carp that is differentiated by its irregular, patchy scaling pattern. The difference in scales is the result of variants in two genes.
Another notable catch during the third sampling event was of a chain pickerel (Esox niger). This was our first catch of this species in Wreck Pond.
This morning we completed our fourth sampling event at Wreck Pond. Our sampling data from prior years suggests that the majority of alewife that migrate into Wreck Pond over the course of a spawning season do so in one or more large waves, often occurring in April. This pattern was born out this past weekend, as we caught 36 alewife over the course of two days (25 the first morning and 11 the second morning). It is possible more would have been caught if not for the change in weather. A sharp temperature drop halfway through the sampling event followed by strong winds and rain, may have affected the alewife spawning run as many fish are known to alter their behavior due to changes in light, temperature, or pressure associated with storms.
Despite the harsh conditions, we continued to sample. Only one golden shiner and one white perch were caught the remainder of the event. Golden shiners are a predominately freshwater fish that often prefer the quieter parts of the river. Interestingly, the golden shiner was caught this morning. Rainwater flowing into the watershed last night and this morning creating high freshwater flows may help explain its appearance lower in the watershed.
I want to thank everyone who has volunteered so far, particularly those who came out this last event.