Remember, it takes two crabs to tango

I have just read the article, "Decreasing male to female blue crab ratio concerns scientists" (July–August, 2012). 

As a brief introduction, I was a commercial crabber out of Crisfield, MD, from the 1970s to early '80s in a family of watermen that worked the Bay at least since the railroad arrived in Crisfield after the Civil War. Our methods were bank trapping and potting for peelers, and we shedded soft crabs.

In the 1980s, I worked a few years for the Chesapeake Bay Foundation Environmental Education Program, managing first the Smith Island Center and then the Northern Bay Mobile Center. For more than 20 years I have been an ecologist with the Delaware Department of Natural Resources and Environmental Control. 

Since management efforts began to conserve sooks, I have been advocating that it takes two to tango. The research of Anson Hines featured in the article gets right to the most fundamental factor in reproduction, i.e. the fusing of gametes.  An additional point, which I think adds value to the case being made is that relative to the overall crab season (a few months) the time window for concentrated crab mating is short (a few weeks).

Based on my crabbing experience, we anticipated two runs of "doublers," (final molt she-crabs) each season; the first in May, the second in August with the May run usually the larger of the two. However big or small the run, it culminated with a "shed off" that lasted only a few days for a large proportion of the total crabs caught, thus reducing even further the window for peak mating. What we were seeing in the floats was occurring on the bottom as well because once we were "shedded out," the run was over.

It seems that there had better be a lot of jimmies available to mate with the soft sooks in the very brief time that they are ready. Hines points out that it takes a while for a jimmy to reload after mating. Unfortunately, if my Pocomoke Sound / Tangier Sound run-pattern observations can be applied generally, once he is ready to go again the vast majority of the sooks are hard and uninterested, mated or not.  

So, it seems that the idea is to somehow facilitate, or prevent disruption of, a condition that maximizes the number of jimmies on the bottom during the brief windows of concentrated mating in order to minimize the number of dry sooks.

Robin M. Tyler, Ph.D.
Dover, DE

 

Windsocks can pose threatto Chesapeake's ospreys

Ospreys can become entangled in fishing lines and nets, as well as other materials they bring to their nests such as plastic bags. We were unaware that our decorative windsock (See photo at right.) posed a risk as well.

Our osprey pair has successfully nested 100 feet offshore from our cottage for five years. During the past two seasons, we have had a windsock at the end of our pier, about 50 feet from the nest. When we first placed the windsock each spring, the male and then the female flew up to inspect it from a few feet away. After that, they paid very little attention to it .

This July, a few days prior to the fledging of her two chicks, the adult female aggressively intercepted a juvenile great blue heron making a direct attack on her chicks. As she was pursuing the first heron, a second heron attacked from a different direction. Fortunately, the female peeled off from her pursuit just in time to intercept the second heron a few feet from the nest. The female vigorously and aggressively chased this heron before returning.

In her heightened state of agitation, she impulsively attacked the windsock a few minutes later. She flew up to the windsock, grabbed the circular rim, and attempted to fly off when she became entangled and fell into the water dragging the windsock and flexible pole behind her.

She was frantically thrashing in the water on her back when we pulled her up on the pier by the flag pole. She was very entangled in multiple nylon cords and sheeting, and her breast area was covered in blood from self-inflicted wounds. She had been gouging at her breast in an effort to remove the nylon cords wrapped around her neck.

A visitor at a neighbor's house removed one nylon cord from around her neck, we cut a second cord and unwrapped her wings to allow her to escape. Talking to her in calm voices seemed to quiet her, and she made no effort to fight us while we removed the cords and windsock from her. She flew off after sitting for a moment and returned to the nest soon after to reassume her mothering duties.

The male was away and unaware of this drama; he got a loud earful from the female when he returned about 10 minutes later. He left after a few minutes and returned with the largest stick he had ever brought to the nest, a probable offering, and a perceived effort to make the nest more secure. The chicks followed his lead and also did some housekeeping.

We are convinced that the female would have not survived if someone hadn't been present to help cut her free shortly after getting entangled. She probably would have drowned, or a few more vigorous gouges at her breast area would have caused fatal bleeding and damage. Fortunately, she recovered and the next morning she fended off another attack by a great blue heron.

Our windsock has four 18-inch long nylon cords. These cords pose a potential hazard to ospreys. Although we have not seen other accounts of similar entanglements in windsocks, we will not fly any windsock with long cords in this location again. We encourage anyone living near osprey nests to avoid displaying items that could pose a similar risk.

Neal & Linda Halsey
Tyaskin MD

 

Pets are part of pollution problem in the watershed

Thanks for beginning the discussion connecting consumer food choices and the Bay's poor health. (See "Protein-rich diet linked to Bay's unhealthy state," May, 2012) Tying this issue, as the article mentions, to human health seems one way to avoid the "preachy" aspect some fear.

We cannot continue to allow fear to shut off discussions that allow people to make informed decisions. Hesitation resulting from coercion needs to cease. The subsequent meat industry spokesperson letters and Tom Horton's commentary are the type of thought-provoking viewpoints that a democratic form of government requires for informed decision-making. But the discussion needs to be broadened to include those surrogate members of many families known as pets. I am not an expert on this, but it seems to me that more attention has been paid to the dangers of pet excrement than the food that they consume.

For example, Salisbury University's report, "Identifying Sources of Fecal Pollution in Shellfish and Nontidal Waters in Maryland Watersheds," found that the failure to clean up after pets, primarily dogs, is a significant source of bacteria in eight Anne Arundel waterways. A Stormwater Center fact sheet states, "EPA estimates that two or three days worth of droppings from a population of about 100 dogs would contribute enough bacteria to temporarily close [for health reasons] a bay and all watersheds within 20 miles of it, to swimming and shell fishing." This dog feces also contributes to a waterway's nutrient load.

The ability to distinguish between animal and human fecal bacteria allowed a number of studies completed in the 1990s to attribute beach closings, as well as runoff from streets and lawns, to pet waste. Recent studies outside the Bay watershed have implicated cat feces in sea otter deaths (although another study challenges this) and found that dog "fecal material may constitute the dominant source of airborne bacteria in Cleveland's and Detroit's wintertime air." A 2009 book, "Time to Eat the Dog: The real Guide to Sustainable Living" initially caused some discussion regarding the ecological/carbon impact of pets. This discussion ranged from support in a New Scientist magazine editorial, "Cute, fluffy and horribly greedy," to the pet industry's claim that pet food protein consists mostly of those parts of the animal humans do not consume. It is time that a more rigorous peer-reviewed approach be taken with this aspect of protein production/consumption, especially as it relates to the Chesapeake.

Rodger Waldman, Director Emeritus,
Chesapeake Audubon Society