Thanks to all who responded to my query regarding cephalopod occurrence in
estuaries.  Here is a summary of the information I received.

Marin Greenwood

[log in to unmask]:

I've done a lot of diving in estuaries, I've never seen an octopus or squid
any where but just inside the estuary only a few hundred yards from the
ocean,
and the water was pure sea water as far as I could tell from the animals I
observed, I have always noticed that when the salinity starts to drop
starfish
and sea urchins disappear, Octopus are not common enough to really make a
judgment, at least on the North Carolina coast.

Martin Attrill:

We regularly caught cephalopods in samples from West Thurrock power
station on the Thames estuary, particularly in autumn when flows
were generally lowes (the maximum salinity here is about  20 PSU -
mid-tide corrected - but we generally sampled over low tide when the
salinity was lower). Most of the specimens were small individuals of
either the squid Alloteuthis subulata or the cuttlefish Sepiola
atlantica. However, occassional large Sepia officianalis were also
caught here.

Rifling through my records the maximum abundances in any one catch 
(500 million litres of water screened) were:

Alloteuthis: 15
Sepiola: 9

So they must be about in the mid-estuary in fairly high number.

Mike Elliott:

In trawling in UK east-coast estuaries and on power station 
screens, we have occasionally taken Eledone (N Sea 
octopus), squid and the small sepiolidae Rossia. The 
records are usually from summer when the salinities are 
higher. (Have a look in the field sampling notes from 
the SEPA East trawling programme in the Forth). Our power 
station records for the Humber to date are mostly from the 
winter although we are now starting monthly sampling to 
cover an annual cycle (details from Nigel Proctor in the 
Institute (of Estuarine & Coastal Studies) 
([log in to unmask]). We have not taken any 
cephalopods during those previous samples but the 
salinities will be less than 15 for most of the time. I 
gather that cephalopods are very poor osmoregulators (like 
echinoderms) and so their capacity for living in estuaries 
is very small. I'll let you know if I come across anymore 
information.

Rodney Rountree:

Lolligocula brevis is a small but very abundant estuarine squid along the
southeastern coast of the United States.  Additionally, Illex illecbrosus
often enters into at least high salinity portions of estuaries in the
northeastern States.

A brief literature search should provide lots of references for L. brevis,
tough you might have more difficulty finding references for Illex (but see
Rountee and Able 1992. Estuaries 15(2):171-185).

Bill Macy:

Greetings Marin- I was forwarded your request for info by a colleague,
since I work with cephalopods. To my knowledge there is but 1 genus of
squid which tolerate brackisk water salinities and that is Lolliguncula. 1
species, Lolliguncula brevis, is found on the US east coast from as far
north as Delaware Bay south into the Gulf of Mexico. Inability to
osmoregulate does seem to be the norm in cephalopods.  Of course a number
of squid and octopuses are found in estuaries in the US and elsewhere, but
only where the salinities are near full strength seawater. I can not tell
you the lower tolerance limit however.
Here are several references which you might find helpful:

Bartol, I. K.  and M. Vecchione. 1997. Distribution of the euryhaline squid
Lolliguncula brevis in the Chesapeake Bay: Relationships betweeen movement
patterns and physical gradients. ICES CM 1997/S:12: 1-4.

Vecchione, M. 1991. Observations on the paralarval ecology of a euryhaline
squid, Lolliguncula brevis (Cephalopoda: Loliginidae). Fish. Bull. 89:
515-521.

John Moverly:

In south eastern Australian estuaries we have collected Idiosepius notoides,
the southern pygmy squid, from dredge samples taken in seagrass beds. This
is an extremely cute species that grows to 2 cm long. (O.K. I tend to like
most animals, but 2 cm long squid really appeal to me.)

Fifteen years ago I work as an environmental biologist with the Queensland
Electricity Generating board We also collected cephalopods on the intake
screens. If anyone is interested I can get the names. The location of the
station was at Gladstone which is 100 km south of the tropics. The greatest
numbers of fish, non-plankton invertebrates particularly prawns including
the cephalopods were associated with fresh water in the river when I suspect
the animals show a reversal of their natural tendency to swim against the
current and were thus more susceptible to entrainment. This suggests to me
the cephalopods were not just incidental to the collections but were part of
the estuarine community.

Andy Cohen:

There are records of octopus in central and southern San Francisco Bay
(typical salinities in the range of 20-30+ ppt), including late 19th
reports of them being commonly harvested on the bayward side of the San
Francisco peninsula. I have not seen them myself in San Francisco Bay, but
have seen one in Santa Barbara Harbor in southern California.




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