Jan
31

Was the movie 'Jaws' the first film to incorporate underwater video of a live great white shark?

The movie Jaws, released June 20, 1975, was a box office blockbuster with a plot that revolved around a great white shark wreaking havoc around a fictional island called Amity off Long Island, New York.  Based on the 1974 novel of the same name by Peter Benchley, the film included impressive underwater video shot by diving and spear-fishing aficionados Ron and Valery Taylor.  The shark was filmed in waters off Australia and the video included a scale model of a dive cage, complete with a small-framed actor, which made the great white seem bigger by comparison. 

However, Jaws was not the first to feature great white sharks in their natural habitat.  The film Blue Water, White Death is a documentary of sharks in their natural habitat which included the first underwater video of great white sharks ever presented.  Released on June 1, 1971, Blue Water, White Death was released four years before the movie Jaws.  Similar to Jaws, Blue Water, White Death includes video shot by Ron and Valerie Taylor along with footage by underwater photographer Stan Waterman.  The film took a full 9 months to complete during which time the film crew, lead by filmmaker and photojournalist Peter Gimbel, traveled between the waters off South Africa and Australia in search of great white sharks.  While the video was made using technology of limited quality compared to today’s standards, the scenes in the film are spectacular for their time.  The adventures of the crew were also documented in the book Blue Meridian: the Search for the Great White Shark (1971) by award-winning writer Peter Matthiessen. 

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Dec
20

How do you differentiate the two species of ladyfish (Elopiformes: Elops spp.) from the western central Atlantic?

Ladyfish (rarely called ‘tenpounders’) are economically valuable and are landed throughout the southeastern United States in both commercial and recreational fisheries (Levesque 2011).  Ladyfish are common in coastal areas throughout most of the western central Atlantic Ocean, including the Caribbean and Gulf of Mexico (Smith and Crabtree 2002).  The genus Elops in the western central Atlantic was traditionally treated as a single species, E. saurus.  This has changed recently with the description of a new species, E. smithi, by McBride and co-workers (2010).  Here’s how to tell the two species apart:

Counts of myomeres (in leptocephala larvae) or vertebrae (in post-larval to adult specimens) are the only known distinguishing morphological characters (McBride and Horodysky 2004, McBride et al. 2010).  E. saurus has 79–87 (usually 81–85) myomeres or vertebrae versus 73–80 (usually 75–78) in E. smithi.  (Number of myomeres = number of vertebrae).The number of myomeres or vertebrae appears to be a good diagnostic character, despite the overlap in range, as this overlap occurred in only 2.9% of the 3,255 specimens examined by McBride et al. (2010).  In counts of leptocephalus pre-anal myomeres or vertebrae, there is no overlap (see following table).

Myomeres should be counted using a compound microscope at 40x magnification, beginning with the first myomere behind the head and ending with the group of three myomeres near the caudal peduncle (McBride and Horodysky 2004).  Vertebrae (in post-larval to adult specimens) can be counted using radiographs and a microscope or by filleting, steaming, scraping, and directly counting the vertebrae.  Vertebral counts include all centra between the proatlas to the urostyle (McBride and Horodysky 2004). 

There are seasonal and geographic recruitment differences between the two species that can help you determine the species by date of capture: E. saurus larvae are most often found during winter through spring versus summer through fall in E. smithi (McBride and Horodysky 2004).  Generally speaking, Elops along the northern U.S. Atlantic seaboard are most often E. saurus while Elops from the Caribbean basin are most often E. smithi (McBride and Horodysky 2004).

The following table presents morphological, seasonal, and geographic comparisons between E. saurus and E. smithi that can help in species-level determinations.  Although it is admittedly difficult to discern the two species from one another, particularly when field-identification is needed, this write-up and associated table should make it more straightforward.

ladyfishtable

Sources Cited:

Levesque, J.C.  2011.  Is today’s fisheries research driven by the economic value of a species?  A case study using an updated review of ladyfish (Elops saurus) biology and ecology.  Reviews in Fisheries Science 19(2):137–149.

McBride, R.S. and A.Z. Horodysky.  2004.  Mechanisms maintaining sympatric distributions of two ladyfish (Elopidae: Elops) morphs in the Gulf of Mexico and the western North Atlantic Ocean.  Limnology and Oceanography  49(4):1173–1181.

McBride, R.S., C.R. Rocha, R. Ruiz-Carus, and B.W. Bowen.  2010.  A new species of ladyfish, of the genus Elops (Elopiformes: Elopidae), from the western Atlantic Ocean.  Zootaxa 2346:29–41.

Smith, D.G. and R. Crabtree.  2002.  Tenpounders (ladyfishes).  Pp. 679–680.  In:  Carpenter, K.E. (ed.), FAO Species Identification Guide for Fishery Purposes:  The Living Marine Resources of the Western Central Atlantic.  Vol. 2:  Bony Fishes Part 1 (Acipenseridae to Grammatidae).  FAO, Rome, Italy.

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Dec
14

In search of giant fish: What was Hemingway’s most coveted game fish?

Papa Hemingway, as he preferred being called over Ernest, was an avid fisherman throughout his life.  He purchased his famous sport fishing boat, the 38-foot Pilar, in 1934 from a company in Brooklyn, New York, for $7,495.  Hemingway named the vessel after a nickname given to his then-current wife Pauline.  The Pilar came fitted with a flying bridge, a live well, and a special modification of the transom to allow large fish to be hauled into the vessel.  Hemingway fished in the Florida Keys and off Cuba and the Bahamas.  He was particularly fond of fishing the Gulf Stream, where he often targeted tuna and marlin. 

His well-honed techniques at successfully landing big tuna and marlin, coupled with his propensity to fish the Gulf Stream using heavy tackle and the many photos of him with landed heavyweights, suggest that Hemingway was most interested in large tuna and marlin.  Anyone having read The Old Man and the Sea probably would guess that Hemingway held a special spot in his heart for marlin.  While speaking of fishing, he often would mention wanting to land a “grander”, a term that refers to 1000-pound-class marlin.  Although the largest of the marlins—Indo-Pacific blue marlin—are legendary heavyweights often referred to as granders, Hemingway’s fishing exploits are outside of the range of that species.  Similarly, the massive black marlin is absent from Hemingway’s area of exploit.  Instead, Hemingway coveted the huge Atlantic blue marlin of the Gulf Current, and he targeted them in his Key West-Havana-Bimini fishing triangle.  Although the Atlantic blue marlin averages only between 300 and 400 pounds, the species’ maximum size of over 12 feet and robust body puts it well into the grander category.  The International Game Fish Association (IGFA) all-tackle angling record, a 1,282 pound monster, was landed off St. Thomas in the U.S. Virgin Islands.  Unfortunately, the weights of some of Hemingway’s biggest marlin remain unknown to this day due to the depredations of sharks while landing the marlin.

Of the tunas, Hemingway probably most eagerly sought the yellowfin, blackfin, bigeye, and Atlantic bluefin tunas, all of which can be caught in Hemingway’s Key West-Havana-Bimini fishing triangle.  Although all of these tunas reach impressive sizes worthy of the most skillful and resourceful of anglers, one species is perhaps the most coveted of all the tunas.  The Atlantic bluefin is often referred to simply as a “giant”.  With a maximum size of over 10 feet, coupled with a torpedo-shaped body made of pure muscle, the Atlantic bluefin may well have been Hemingway’s most prized fish.  The IGFA all-tackle record tipped the scales at about 1,497 pounds for a giant bluefin caught off Nova Scotia in 1979.

In celebration of Hemingway’s passion and aptitude for big game fishing, the Hemingway International Billfish Tournament is held each year near Havana, Cuba, where anglers target marlin, tuna, wahoo, dolphinfish, and other heavyweights over a several-day period.  A full-size replica of Hemingway’s Pilar, complete with several fighting chairs, can be seen on display at the Worldwide Sportsman store in Islamorada, Florida.  The original Pilar is on display in the Museo Ernest Hemingway in Cuba, near Havana.

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Dec
13

Tips in identifying the searobins (Scorpaeniformes: Triglidae) along the Atlantic and Gulf coasts of Florida

Searobins are small to medium-sized benthic fishes (to 45 cm total length) that are common along Florida’s coastlines.  Although they are not targeted in commercial or recreational fisheries, searobins are captured in bottom trawls intended for shrimp or captured during epifaunal research surveys.  Searobins are important members of the benthic community and can amount to considerable biomass in some areas of Florida.  There are a total of 15 species within the family Triglidae in Florida waters.  First, one needs to determine which of the two genera his or her specimen belongs:

Bellator versus Prionotus

The genus Bellator can be distinguished from Prionotus by the absence of scales on the opercular membrane above the opercular spine.  There are usually 11 dorsal spines (rarely 10 or 12).  The first or second dorsal spines of males of Bellator species often end in long filaments (except in B. brachychir) (Richards and Miller 2002).  Also, species of the genus Bellator are relatively small (less than 17 cm standard length) (Richards and Miller 2002).  Finally, species of the genus Bellator are not normally found in inshore waters below about 20 m depth such as shallow bays, inlets, or estuaries.

In contrast to Bellator, the genus Prionotus never has a long, filamentous second dorsal spine.  Also, the dorsal spines usually number 10 (rarely 9 or 11) in Prionotus, and the opercular membrane is partially scaled above the opercular spine (Richards and Miller 2002).  Species of the genus Prionotus are often found in inshore waters, including bays and inlets.

See below for determining species within each genus.

Bellator Species

If you determined that your specimen falls within the genus Bellator, use the following table to help narrow down the possible species by geographic range or depth in Florida waters.

 searobinstable1

Bellator Morphological Characters by Species

The following characters are based on Richards and Miller (2002).

Bellator brachychir

  • No filamentous dorsal spine present
  • First free pectoral fin ray considerably longer than length of pectoral fins
  • Usually less than 11 cm standard length (maximum size is 16 cm)

Bellator egretta

  • Males with elongate filament extending from the first dorsal spine
  • Head very spiny, including sharp spine in front of eye, and long opercular and preopercular spines
  • First free pectoral fin rays shorter than length of pectoral fins
  • Usually less than 10 cm standard length (maximum size is 15 cm)
  • Alternating light and dark pigment appearing as brown patches or bands on upper one or two pectoral fin rays

Bellator militaris

  • Males with elongate filaments extending from the first and second dorsal spines
  • Dorsal-most pectoral fin rays marked with black and white bands
  • No dark ventral margin on pectoral fin
  • Colors in life are rosy with yellow lines along mid-body extending to caudal fin
  • Usually less than 11 cm standard length (maximum size is 16 cm)

Prionotus Species

If you determined that your specimen falls within the genus Prionotus, use the following table to help narrow down the possible species by geographic range or depth in Florida waters.

searobinstable2

Prionotus Morphological Characters by Species

The following characters are based primarily on Richards and Miller (2002), McEachran and Fechhelm (2005).

Prionotus alatus

  • Lower pectoral fin rays very long, reaching past the posterior margin of anal fin
  • Pectoral fins with black bands
  • Small nasal spines present (can be detected by running finger along snout region towards snout tip)
  • Maximum size is 20 cm standard length
  • Reported to hybridize with P. paralatus between Gulfport and Panama City

Prionotus carolinus

  • Branchiostegal rays dark (dusky or black)
  • Pectoral fins attractively patterned throughout with spots in fresh specimens (see following figure)
  • Dorsal fin with a single dark non-ocellated spot between 4th and 5th spines
  • Can be distinguished from P. scitulus by the dark dorsal spine mentioned above
  • Can be distinguished from P. martis by the dark dorsal spine and by range
  • Caudal peduncle with white blotch on dorsal side
  • Maximum size is 38 cm standard length

Searobins1

Prionotus evolans

  • Nasal spines are absent
  • Pectoral fins dark (patterned with very narrow, closely spaced, dark lines) (see following figure)
  • Pectoral fins long, reaching posterior portion of anal fin
  • Two distinct thin dark stripes along sides to caudal peduncle, contrasting with light background color
  • Maximum size is 45 cm standard length (1.55 kg all-tackle record)

 searobins 2

Prionotus longispinosus

  • Branchiostegal rays very light-colored (whitish)
  • Pectoral fins with small light-colored spots
  • Caudal peduncle without a light-colored blotch on dorsal side
  • Maximum size is 35 cm standard length

Prionotus martis

  • Throat (gular area) is completely scaled
  • Branchiostegal rays are dark (dusky or black)
  • Gill rakers on lower limb of first arch usually 9 (range = 8–11)
  • Dorsal fin with two distinct dark spots between 1st and 2nd, and 4th and 5th spines (see following figure)
  • Body heavily spotted
  • Small sized (maximum size is 18 cm standard length)

Prionotus ophryas

  • Nasal cirri are present
  • Preopercular spine long, reaching beyond posterior edge of operculum
  • Pectoral fins very long, reaching well beyond posterior edge of anal fin
  • Pectoral fins rounded
  • Body color is variable, but not silvery
  • Usually in 18–64 m depth
  • Small sized (maximum size is 20 cm standard length)

Prionotus paralatus

  • Nasal spines are absent
  • Preopercular spine is long, reaching just beyond operculum
  • Pectoral fins with dark spots and some scattered pinkish coloration throughout
  • Reported to hybridize with P. alatus between Gulfport and Panama City
  • Most abundant in 60–120 m depths
  • Small sized (maximum size is 18 cm standard length)

Prionotus roseus

  • Pectoral fins long, reaching or approaching the posterior edge of anal fin
  • Dorsal free ray of pectoral fins short, not reaching posterior edge of pelvic fins
  • Pectoral fins with bright blue or dark ocellated spots throughout (sometimes not ocellated)
  • Pectoral fins with dark ventral edge (edge not blue)
  • Small sized (maximum size is 20 cm standard length)

Prionotus rubio

  • Nasal spines are absent
  • Pectoral fins long, lowermost rays reaching beyond the posterior edge of anal fin
  • Pectoral fins uniformly very dark (blackish) with distinct blue margin on ventral edge (see following figure)
  • Small sized (maximum size is 23 cm standard length)

searobins3

Prionotus scitulus

  • Throat (gular area) is completely without scales
  • Branchiostegal rays light-colored (whitish), never dusky or black
  • Gill rakers on lower limb of first arch usually 11 (range = 10–13)
  • Dorsal fin with two distinct dark spots between 1st and 2nd, and 4th and 5th spines (see following figure)
  • Body spotted throughout
  • Maximum size is 25 cm standard length
  • Often found in shallow bays

 searobins4

Prionotus stearnsi

  • Mouth with small bony knob on ventral side at symphysis
  • Throat (gular area) completely scaled
  • Pectoral fins relatively short (not reaching beyond origin of anal fin)
  • Pectoral fins very dark (blackish)
  • Trunk light colored (silvery)
  • Small sized (maximum size is 18 cm standard length)

Prionotus tribulus

  • Head is large and broad
  • Total gill rakers on first arch usually 8–16
  • Pectoral fin with broad, dark vertical bands (may be narrow in Gulf of Mexico specimens)
  • Maximum size is 35 cm standard length

Sources Cited:

Hastings, R.W.  1979.  The origin and seasonality of the fish fauna on a new jetty in the northeastern Gulf of Mexico.  Bulletin of the Florida State Museum, Biological Sciences 24(1):1–124.

McEachran, J.D. and J.D. Fechhelm.  2005.  Fishes of the Gulf of Mexico, Volume 2: Scorpaeniformes to Tetraodontiformes.  University of Texas Press, Austin, TX.

Richards, W.J. and G.C. Miller.  2002.  Searobins.  Pp. 1266–1277.  In:  Carpenter, K.E. (ed.), FAO Species Identification Guide for Fishery Purposes:  The Living Marine Resources of the Western Central Atlantic.  Vol. 2:  Bony Fishes Part 1 (Acipenseridae to Grammatidae).  FAO, Rome, Italy.

Robins, C.R. and G.C. Ray.  1986.  A Field Guide to Atlantic Coast Fishes of North America.  Houghton Mifflin Co., New York, NY.

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Dec
12

What kinds of animal remains contribute to the sediment of deep continental slope waters off southeastern Florida?

What types of invertebrates can be identified from the remains contributing to the sediment in continental slope waters?  An ANAMAR biologist set out to learn just what groups of invertebrates could be identified from sediment collected in the deep waters off Port Everglades Harbor, Florida.  The sample was collected using a custom-made bucket sampler that was towed a short distance across the sediment surface in 664 feet of water off Port Everglades Harbor (Fort Lauderdale), Florida. 

About 2 gallons of the sediment was sieved through a 2-mm screen.  An additional 15 ounces of the sediment was wet-sieved with a 0.8-mm fine-mesh screen to uncover the remains of smaller invertebrates.  The sample matrix was mostly greenish-gray silty fine sand, most of which was washed away during the sieving process.  The remaining shells and other hard objects were left to dry over a few week’s time.  The remains were then identified and photographed. 

southeasternflphoto1

So what was found?

The sample contained:

  • Foraminiferidas (commonly called foraminifera or forams)
  • Mollusks
    • Bivalves
    • Sea butterflies of the order Thecosomata (previously of Pteropoda)
    • Other gastropods
  • Crustacean (crab and shrimp) remains
  • Echinoid (sea urchin) spines and tests

southeastflphoto2

Are any of these remains fossilized? 

All of the shells and other remains appeared to be of Holocene age (modern).  Thus, none of the remains represent fossils.  Based on the age of the animal remains, it appears that the sediment surface is mostly recently deposited material.  However, the silt component of the sediment sample may have been older than the shell component of the sample.

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Dec
01

What animals can be found in the sediment at Canaveral Harbor, and what can they tell us about the age of the sediment?

canaveral sed photo 1

Although harbor sediment is often subjected to physical, chemical, toxicological, and bioaccumulation analyses, the biological properties often go unnoticed and unappreciated during such testing.  What can the biological properties—the critters inhabiting the sediment—tell us about the age and history of the sediment?  An ANAMAR biologist set out to learn just that, by sieving extra material from a recent sediment sampling event at Canaveral Harbor, Florida.

About 12 gallons of extra sediment sampled from Canaveral Harbor, Florida, was wet sieved with a 2-mm screen to uncover modern and fossil animal remains.  The sample matrix was mostly gray-green colored clay which was washed away during the sieving process.  The remaining shell hash component left in the sieve showed that it contained at least the remains of mollusks.  The shells and other hard objects were left to dry over a few week’s time.  The remains were then identified and photographed.

 

So what was found?

The sample contained:

  • Crustacean (crab and shrimp) claws including the purse crab genus Persephona
  • Barnacle shells
  • Echinoid (sea urchin) spines and other remains
  • Mollusk shells
    • Ark shells of the order Arcoida
    • Tusk shells including the genus Dentalium
    • Wentletraps including Epitonium cf. rupicola
    • The limpet Diodora cf. floridana
    • The land snail Polygyra septemvolva (Florida flatcoil)
  • Fish remains
    • A tooth from Carcharhinus isodon (finetooth shark)
    • Vertebrae from teleost (bony) fishes
    • A pectoral spine from the sea catfish family Ariidae

canaveral sed photo2

Are any of these remains fossilized? 

It is not always easy to differentiate a fossil from the remains of modern animals, especially when considering the remains of mollusks having calcium carbonate shells.  However, we can say with certainty that the limpet shell is a fossil because the species Diodora floridana lived only during the Pleistocene (it has been extinct for thousands of years [Peterson and Peterson 2008]).  The Florida flatcoil shells may also represent fossils as they appeared to contain consolidated mineralized material filling the internal voids, and were a much darker than modern shells of this species.  The finetooth shark tooth also represents a fossil although this species still occurs around Florida today.  Most shark teeth found in sediment or on the ground are fossils because, although sharks are abundant in today’s oceans and they continually lose and replace teeth throughout their lives, it takes a build-up of teeth over thousands or millions of years for them to be numerous enough to be easily found. 

Most of the remaining shells are Holocene in age (modern).  Overall, the shells within the sediment range in age from Holocene (recent) to the Pleistocene (12,000 to 2.6 million years ago), based on the taxonomy of the animal remains.  The presence of the land snail Polygyra septemvolva among the remains of the marine animals suggests that the sediment had been mixed with other deposits originating from terrestrial sources.

canaveral sed photo3

Source Cited:

Peterson, C. and B. Peterson.  2008.  Southern Florida’s Fossil Seashells.  Blue Note Publications, Inc., Cocoa Beach, FL.

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May
02

Important differences between FDA action levels given in the SERIM and those given by FDA

FULL WRITE-UP:

Action levels provided by the U.S. Food and Drug Administration (FDA) are used as screening benchmarks during Tier III testing evaluations under Section 103 of the Marine Protection, Research, and Sanctuaries Act of 1972 (MPRSA).  These action levels are based on human health and economic considerations and represent limits above which the FDA can take legal action to remove products from the marketplace (EPA and USACE 1991, known as the ‘Green Book’).  The Southeast Regional Implementation Manual (EPA and USACE 2008, known as the ‘SERIM’) provides guidance for MPRSA Section 103 testing evaluations in the southeastern United States.  Some discrepancies exist between the action levels provided by the FDA and those given in the SERIM.  The table below compares action levels between the SERIM, the source document to the SERIM (FDA 2001), and the most current FDA action levels (FDA 2011).

The action level presented in the SERIM for cadmium in bivalve tissue is switched with that of crustacea (see table above).  The SERIM applies the crustacea action levels to include polychaete worms as the FDA lacks any action levels intended for polychates.  The action levels given in the SERIM for mercury are intended for use specifically for methylmercury (FDA 2001 and 2011) rather than for total mercury.

The SERIM (Section 3.3.2.2 [page 24]) and the Green Book (Section 6.3 [not paginated]) suggest the reader use an updated version of the FDA action levels when available.  FDA action levels have been updated since the SERIM was published in 2008 and, therefore, it is useful to refer to FDA (2011) for some or all action levels rather than Appendix H of the SERIM.  However, since FDA (2011) omits arsenic, cadmium, chromium, lead, and nickel, the values given in FDA (2001) may, with the approval of USACE, continue to be used as screening benchmarks for these metals in Tier III evaluations.

Sources Cited Above:

U.S. Environmental Protection Agency and U.S. Army Corps of Engineers.  1991.  Evaluation of Dredged Material Proposed for Ocean Disposal, Testing Manual [Green Book].  EPA 503-8-91-001.  EPA, Office of Marine and Estuarine Protection and Department of the Army, USACE, Washington, DC.

U.S. Environmental Protection Agency and U.S. Army Corps of Engineers.  2008.  Southeast Regional Implementation Manual (SERIM), Requirements and Procedures for Evaluation of the Ocean Disposal of Dredged Material in Southeast U.S. Atlantic and Gulf Coast Waters.  EPA Region 4, Atlanta, GA, and USACE South Atlantic Division, Atlanta, GA.

U.S. Food and Drug Administration.  2001.  Fish and Fishery Products Hazards and Controls Guidance, Third Edition — June 2001 [online document].  Accessed 02/25/11 online at:  http://www.fda.gov/Food/‌GuidanceComplianceRegulatoryInformation/GuidanceDocuments/Seafood/FishandFisheriesProductsHazardsandControlsGuide/default.htm.

U.S. Food and Drug Administration.  2011.  Fish and Fishery Products Hazards and Controls Guidance, Fourth Edition — April 2011 [online document].  Accessed 01/09/12 online at:  http://www.fda.gov/Food/‌GuidanceComplianceRegulatoryInformation/GuidanceDocuments/Seafood/FishandFisheriesProductsHazardsandControlsGuide/default.htm.

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