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Humboldt Bay - Collection Journal and Maps, 1966

Map showing collection areas around Humboldt Bay, CA.

Humboldt Bay, with its approximate 40-miles of shoreline was about the same size as San Diego Bay, but much less of it was developed and from a collecting standpoint it was far more attractive. Whereas only two decent spots could be found in all of San Diego Bay, at least seven good spots were accessible here and several of these covered large stretches of relatively natural shoreline. As indicated on the enclosed map, all of the mouth and the area directly opposite the mouth had been built up with artificial riprap and most of the north spit was fenced and posted by private lumbering companies. As usual, large areas of the northern and southern most portions of the bay were soft and swampy.

An additional point of interest was the presence of the P.G. & E. Atomic Power Plant located inside the bay in the Fields Landing area. Humboldt Bay offered a sharp contrast in water depths. Apparently, there was a deep water channel extending from the mouth to the town of Eureka. In Area 1 (see below), I stood on the low tide edge of a wide mudflat and less than a city block away lay a large German freighter loading wood pulp. I asked one of the old-timer's digging clams if he had seen geoducks and he said that they were found on one of the islands in the bay accessible only by boat. Standing on a thick Zostera bed on a cool, sunny morning and smelling the delicious odor of burning redwood from a nearby lumbering company was a nice experience.

Each of the areas covered is listed and described in detail below:

Area 1 was the northern most spot covered in the bay and consisted of a ¼ mile long stretch of wide flat that varied from soft to fairly firm sandy mud. A very good amount of tidal zone was exposed at minus tide and Zostera was present in scattered stretches at the lower level. A few turn-able rocks were seen here and in the northern most portion of this area there were a number of burrow ridden, broken-off pilings which had been reinforced to no avail by cement jackets. Under rock life was not too rich but the pilings offered a very dense colonization of huge Thais lamellosa with its egg clusters.

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Map showing collection areas in Humboldt Bay on California's northern coast. Descriptions of the numbered areas can be found in the text to the left.

This was one of the few spots found in the entire bay that had bottom in the lower tidal zone that was firm enough to do some deeper digging. The results of this, even among the scattered Zostera, was not very productive. Although Clevelandia was seen, no Urechis could be turned up down to 24" deep and no Callianassa was found. The only real products of this deeper digging were huge specimens of Neanthes brandti and Schizothaerus capax. The water at tide edge dropped off sharply to form the deep water channel leading to the mouth. By far the most distinctive find here was the new species of lugworm, Arenicola pusilla. In one block long stretch among the broken off pilings I dug 15 specimens and saw the coiled castings of at least that many more. They were not seen elsewhere in this area.

I saw an old-timer with a clam hook pulling up large 5" long specimens of Saxidomus nuttallii and their narrow holes were abundant. As an overall rating, this would be classified as a fairly good collecting spot.

Characteristically abundant species found here:

Area 2 was a 1/2-mile long stretch of clean, sandy, steep sloping beach with riprap rocks and a boat launch at the southern end and a small, muddy, rocky point at its northern limit. Except for this rocky point and one other, tidal zone exposure was poor and Zostera growth was also lacking except in clusters below the water edge. Strangely, the riprap rocks here did not offer much in the way of attached animal life and the only distinctive find on the boat launch pilings, underneath and out of the sunlight, were dense clusters of both brown and white color variations of Metridium senile.

Under side of rock life was not much to speak of, but buried under small, scattered rocks on the muddy, rocky point where the largest and most abundant specimens of Neanthes brandti ever seen. Ten holes dug produced eight specimens all over 12" long and several stretched to 24". Also abundant here on and under these scattered rocks were Anthopleura artemisia and Schizothaerus capax. The only new species was Mesochaetopterus taylori found in one small area just south of the boat launch. Six specimens were dug and the tubes of at least twelve were seen. I tried to dig out a complete specimen but the clean sand would collapse at more than 14" deep. This rated as less desirable as a collecting spot than Area l.

Characteristically abundant species found here:

Area 3 was a 1/3-mile long stretch of very steep sloping sandy shore almost directly opposite the mouth of the bay. Due to this steep slope, tidal exposure was poor and no Zostera growth was seen here at all. There were a few small rocks on one flat point but other than this, the area as a whole was steep and barren and looked very much like it had been recently and artificially formed. This was the poorest area covered and no new species were found here. The only animal that could be considered as characteristically abundant was Pista pacifica.

Area 4 was one of, if not the most interesting spots covered. It started at the riprap rocks at the tip of the southern spit and worked southward along the shoreline of a small cove, around a steep sloping sandy point and into another larger and more protected cove that exposed dense growths of Zostera on a wide, soft mudflat at minus tide. The total shoreline covered amounted to approximately ½-mile and the degree of tidal exposure in both cove areas was good. The turnable riprap rocks showed a fairly rich and very interesting display of under rock life in that four new and different species were found here. They were:

Both Evasterias and Crossaster were supposed to be more northerly forms. The first small cove just inside the riprap uncovered at the low tide level a thick clay bottom that was literally covered with siphons of Zirfaea pilsbryi and also a series of burrow ridden piling stumps that turned up another new species Bankia setacea. Other pilings displayed the richest and most colorful growth of Tubularia crocea yet seen.

The second cove was dense with Zostera growth and very rich in both Schizothaerus and Saxidomus spp., but a shovel was just about useless due to the very soft bottom. Probably the strangest feature of this area was a large, deep, isolated pool located at least two city blocks from the nearest water edge that was filled with dense, live Zostera. Both Phyllaplysia taylori and Idothea resecata were abundant in it. It must have had a regular exchange of fresh seawater but I don't see how unless it had a subterranean source. Needless to say, this rated as a rich collecting area.

Characteristically abundant species found here:

Thick clay cove area

Soft mud and Zostera cove area

Area 5 was a short 1/8-mile long stretch of soft, muddy flat scattered with small rocks and piling stumps. Tidal zone exposure was fair and only scattered Zostera was seen. The under side of rock life was again fair and there seemed to be a definite clustering of animal life shallowly buried under and around these scattered rocks. New species first found here but later in many other spots in the bay were Schizothaerus capax, Saxidomus giganteus and the small, red, unidentified annelid (HB#2) commensal in mud tubes on the carapace of female Pinnixa faba inside Schizothaerus capax. The only other really characteristically abundant animal found here was Spirontocaris paludicola under rocks and timber debris. Although much less interesting than Area 4, this would still be rated as a fair collecting spot.

Area 6 was the first accessible spot just past the fenced and posted area on the south spit. It covered approximately 1/3 of a mile of very soft, Zostera covered mudflat. A tremendous amount of tidal zone was uncovered here at a good low tide and it was crisscrossed by many small tidal channels, one of which almost got me in trouble because it filled up faster than I thought it would with the incoming tide and I almost waited too long to re-cross it. There was no rock material to be found here at all. This was one of the areas in the bay in which a shovel was useless except as a walking stick in the soft mud. Clam life was very rich but if you did not have a 'hook', it was easier to dig them with your hands than with a shovel. An example of this was the grandfather and two grandsons who dug them by crawling across the soft surface probing for clams with their hands. Consequently, it was only possible to observe exposed animal life here.

Two new species found were the unidentified small, blackish brown tectibranch (HB#5) and the exposed brown nemertean (HB#6). Despite the inaccessibility of buried life, this still proved to be a rich area in exposed forms.

Characteristically abundant species found here:

Area 7 was another 1/8-mile long stretch of soft, Zostera covered mudflat. The amount of tidal exposure at minus tide was large and once again digging to any good depth was near impossible in the very soft bottom. The only rock material amounted to a few scattered rocks in the high tide zone and under rock life here was not rich. No new species were found but I had more luck taking Saxidomus nuttallii here than anywhere else to date. I easily dug 25 large clams in less than an hour and it wasn't hard work because they were shallowly buried. This was a rich area for Saxidomus but rated only fair for other tidal life.

Characteristically abundant species found here:

On a second trip to Area 4, three additional new species were found. They were:

A brief summary of Humboldt Bay showed that although Clevelandia ios was seen, not one specimen of either Urechis caupo or Scleroplax granulata was dug. Also, and surprisingly, not a single specimen of either Callianassa or Axiothella rubrocincta was found and only one specimen of Pectinaria californiensis was uncovered in the entire bay.

Three other notable points were the scarcity and smallness of specimens of Mytilus edulis, the abundance and hugeness of Neanthes brandti and the distinctive colorfulness of Tubularia crocea.

Of the 122 different species found in Humboldt Bay, all were personally collected between the limits of the high high tide and the low low tide zones in the areas indicated and only live specimens found were included here.

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The marshy tidal flats found in Humboldt Bay.

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