Fish Parasites – Will Cold Smoking Kill Them?

(CDFW photo by Debra Hamilton)

(CDFW photo by Debra Hamilton)

Question: I recently caught a number of trout that had what I believe to be parasites called “Lernaea” attached to them in various places. I know after reading another posting from this column titled “Parasites and Trout” that these “are killed during cooking, effectively eliminating any possibility of infecting humans eating the fish,” but I am considering smoking them. Would these parasites pose any threat if the trout were cold smoked rather than cooked, or would the curing that takes place eliminate any threat as well? Presumably if they were hot smoked there would be no threat because the fish are then cooked. I appreciate any info you can provide. Thanks. (Keith R.)

Answer: First off, Lernea and other external parasitic copepods of fish are not transmissible to humans.

As far as fish brining and smoking (even hot smoking), according to Dr. William Cox, California Department of Fish and Wildlife (CDFW) Program Manager of Fish Production and Distribution, there are other parasites that warrant more serious consideration, such as anasakine nematodes and human tapeworms. These parasites are not reliably killed by brining, smoking or even freezing. The only way to ensure they are killed is to thoroughly cook your fish. Generally, we are not worried about those parasites in freshwater fish caught in California. But, nematodes are a concern and they are commonly found in saltwater fish of all species.

For any additional questions related to human health issues, please contact the California Department of Public Health www.cdph.ca.gov.


How are deer hunting zones determined?
Question: What is the history of the deer hunting zones in California and how were they formed and decided upon? I assume the decision on the zone boundaries, tag quotas, seasons, etc. involved the Fish and Game Commission, science gathered by wildlife biologists and land managers, the public, etc. When did the random drawing fund-raising tags for big game begin? (Travis B.)

­Answer: California deer zones were originally developed in 1978 to reduce deer hunting pressure in certain areas of the state. Here’s how they came about.

In the late 1940s and early 1950s, there was a tremendous demand for lumber to satisfy a growing demand for housing. Timber harvest created large areas of early successional habitat upon which mule and black-tailed deer thrived. By the 1960s and 1970s, changing land use practices began to change the landscape. Fire suppression, grazing and commercial/residential development projects caused the loss or degradation of deer habitat. With the reduced areas of deer habitat (and land available for hunting), the result meant higher concentrations of hunters in certain areas.

As land use practices changed and deer habitat was lost, by the winter of 1966-67 significant decreases in deer numbers were also observed. These low deer numbers were likely due to a combination of factors including habitat loss and degradation, and severe winter conditions.

Harvest numbers continued to show a downward trend into the 1970s and it was during this time that CDFW began to implement more conservative deer hunting regulations. Fewer deer and intense hunter pressure (particularly on mule deer) required new conservation measures to sustain deer populations. To relieve hunting pressure on mule deer, the decision was made to go to a zone system.

In 1978, CDFW used the best available information (along with the public’s input) to establish hunt zones that reflected the biological needs of the state’s 81 deer herds and their associated habitats. Currently, California has 44 hunt zones with some designated as premium hunts available through a lottery system. The zone/tag quota system currently in place is the result of the changes that began in 1978.


Handing off?
Question: Can two people be in a boat (both with licenses) with one person diving and handing abalone to the other person on the boat? (Janet R.)

Answer: No. Abalone may not be passed to another person until they are tagged and recorded on the abalone report card. “Cardholders … shall not transfer any abalone from his or her immediate possession unless they are first tagged and recorded on the report card” (CCR Title 14, section 29.16(b)(1)). After they are tagged and recorded, the diver can give his or her daily bag limit of abalone to the other person, but the diver cannot take any more abalone that day.


Can mice be used as bait?
Question: Is it legal to use mice as bait for stripers and bass? (Chris M.)

Answer: Despite the fact that there are many artificial lures on the market that look like mice, real mice may not be used in inland waters. Only legally acquired and possessed invertebrates, mollusks, crustaceans, amphibians (except salamanders), fish eggs and treated and processed foods may be used for bait (CCR Title 14, section 4.00). In ocean waters, there are no restrictions on using mice as bait for stripers.

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Carrie Wilson is a marine environmental scientist with the California Department of Fish and Wildlife. While she cannot personally answer everyone’s questions, she will select a few to answer each week in this column. Please contact her at CalOutdoors@wildlife.ca.gov.

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