Purpose and Frequencies of Tracking Collars?

Mountain lion collared by researchers shows up on a San Diego trailcam, courtesy of CDFW.

by Carrie Wilson
11-9-2017
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Question: My daughter and I have a huge interest in our local wildlife. We live in the foothills of the Santa Monica Mountains. I have been interested in radio and emergency communications since my childhood. I was hoping you could educate us regarding what tracking collars are being used around my house and what frequencies the collars are using to transmit over. (Anthony D.)

Answer: Thank you for your interest in California’s wildlife. When wildlife researchers affix radio collars to a wild animal, their primary purpose is to understand the animal’s movements in a natural setting. Animals may alter their behavior in response to people intentionally approaching them. If this happens to an animal that has a tracking collar, the results of the study can be altered, resulting in inappropriate conclusions. This is called introducing “bias” into the data, which is something that scientists always try to minimize.

Therefore, as a matter of maintaining scientific integrity as well as ensuring the safety of the study animals and people (imagine approaching an injured mountain lion), we do not disclose the frequency of the tracking collars we deploy on animals.

But beyond that, while a radio collar may broadcast on a set frequency, it takes sophisticated tracking equipment to interpret that signal. Therefore, the common person would not recognize it on conventional radio equipment. Scientists take great care to be sure that the signal coming from the collars will not conflict with known existing signals.

Squid jigs
Question: I have a question regarding the regulations for market/jumbo squid. Section 29.70 in the Ocean Regulations simply states that “squid may be taken with hand-held dip nets.” However, I have seen many guys using squid jigs of all types to catch squid. The jigs have no hooks but are a circular nest of pins around a lure body that lightly snag the squid when they attack the jig. This seems like a common method of take but I don’t see it listed in the regs. Is using a squid jig legal to catch squid south of Pt. Conception? (Mark N.)

Answer: Squid fishing regulations can be found in the general mollusks section of the regulations book beginning on page 36. Here it says, “Except as otherwise provided in this article, saltwater mollusks, including octopus, may be taken only on hook and line or with the hands” (California Code of Regulations Title 14, section 29.10). Therefore, since squid may be taken with hook and line, the squid jig may be used as a type of hooking device. Squid jigs are legal for catching squid throughout California.

Hearing conditions vs. rifle silencer?
Question: I have substantial hearing loss and my doctor recommends surgery to correct my problem. The issue is that my hearing would be very sensitive to noise, and shooting a rifle could actually damage it greatly. I don’t want to have to give up hunting though, so is there an exception for the hearing impaired where I could use a silencer on my rifle? (Carlos M.)

Answer: No. Section 33410 of the California Penal Code regulates the possession and use of silencers, also known as suppressors, with very specific exemptions for the military and law enforcement personnel. Penalties for mere possession in California are quite severe.

California Penal Code Section 33410 states that any person, firm, or corporation who within this state possesses a silencer is guilty of a felony and upon conviction thereof shall be punished by imprisonment pursuant to subdivision (h) of Section 1170 or by a fine not to exceed $10,000, or by both that fine and imprisonment. There are no exceptions for hunting or for people suffering from hearing impairment.

Measuring striped bass?
Question: The other day I caught a striped bass that was between 17 and 18 inches. When I opened the tail it measured 17 inches, but when I barely squeezed the tail, it measured 18 inches. What’s the proper way to measure striped bass? (Tou T.)

Answer: Legal-sized striped bass must measure at least 18 inches total length. Total length is defined in the regulations as “the longest straight-line measurement from the tip of the head to the end of the longest lobe of the tail” and specifies that the tip of the head “shall be the most anterior point on the fish with the mouth closed and the fish lying flat on its side” (CCR Title 14, section 1.62). The best way to measure fish to get the longest total length is to lay the fish down flat on a flat surface, pinch the mouth shut and measure to the longest point of the caudal (tail).


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 [email protected].


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