9.1.1 Northeast

Diving in Northeastern waters can be described as an exciting and chilling experience. Generally, the best diving conditions in terms of water temperature, sea state, and underwater visibility are from June through October. As one progresses east and north along the New England coast, water temperatures decrease and underwater visibility increases.

Water temperatures near the surface during the spring and summer when a substantial thermocline exists, range from 50° to 70° F. Bottom temperatures at 100 feet range from 48° to 54°F. During the winter months the water column is essentially homogeneous with temperatures going as low as 28.5° F. Subzero air temperatures and strong winds result in chill factors as low as 70° to 80° F below freezing. The diver must exert caution not to extend his time in the water or be exposed in a wet condition out of water to the point where he loses the manual dexterity of his hands and feet. Three-eights inch wet suits and variable volume dry suits are becoming the standard dive suits for winter diving in the Northeast (See Paragraph 9.3.2).

Underwater visibility is primarily a function of sea state and vertical turbulence in the water column. Horizontal visibility of 50-80 feet is occasionally seen throughout the year, usually associated with periods of calm seas. Proximity to the land mass or estuaries/harbors results in decreased visibility due to the mixing of fresh water with salt and the associated load of suspended material. One to several times a summer "red tide" conditions will exist with visibility of less than one foot. Coastal waters within the Gulf of Maine have an average visibility range of 25 to 35 feet, while visibility in waters south of Cape Cod averages 10 to 15 feet.

Several species of brown algae comprise the large kelp of the New England coast. None of these kelp

form surface canopies as do those off California (See Paragraph 9.3.5). New England kelp will occasionally extend 25 feet off the hard ocean bottom and, although they present a formidable looking barrier to divers, they are virtually harmless in terms of the diver becoming entangled. Generally, these algal plants are sparsely distributed and seldom project more than 6-8 feet from the bottom.

Currents along the New England coast are primarily tidal in origin and generally do not exceed 0.5 knots. Faster currents may be encountered in channels and river mouths. Caution should be exerted especially while diving in strong currents and cold water because of the potential for overbreathing the regulator. Surf conditions are modest compared to California surf but are especially hazardous along rocky, precipitous coastlines such as the coast of Maine. Short period waves of 5-10 feet in height create very rough and turbulent sea states along such rocky coasts and can sweep divers over barnacle covered rocks.

Hazardous Marine Animals. Relatively few species of fishes and invertebrates are potentially harmful to divers off the New England coast. Several species of sharks are occasionally seen, but are very rarely harmful to divers. They are the mako, dusky, tiger, great white, hammerhead and the most commonly encountered blue shark. Occasionally the filter feeding basking shark will be mistaken for a dangerous shark. The torpedo ray (electric ray) (See Figure 15-18), cow nosed ray, and sting ray are found off southern New England (Cape Cod and South). Documented diver-shark or diverray encounters are relatively rare along the New England coast.

The most bothersome fish is the goosefish which may weigh as much as 100 pounds and grow to 5 feet in total length. The goosefish lies partially buried on the ocean floor waiting for unsuspecting "meals" to pass by. This fish is approximately one-half head and mouth and one-half tail. It is indeed a formidable adversary that may startle and perhaps grab onto a diver. The wolffish is another bottom oriented creature that is highly respected by fishermen and divers for his strength and aggressiveness when bothered. The six large canine tusks are capable of considerable damage as many fishermen have found when boating this species.

The green sea urchin with its many stout spines at easily puncture a rubber wet suit can also

inflict injury to divers. Unless the tip of the spine is removed surgically from the diver it will result in a painful "lump" under the skin for months or years. The green sea urchin is found in very dense concentrations on hard substrates to depths of 50 to 60 feet.

9.1.2 Mid-Atlantic

Water temperatures off the Mid-Atlantic States will range, during the summer months, from about 60° to 75° F. During winter, water temperatures will drop as low as 38° to 45° F in the northern portions and 45° to 55° F in the southern portions.

Visibility in these waters is highly variable. depending on time of year, weather conditions. prevailing currents and distance from shore. It is not uncommon to have visibilities up to 60 feet offshore (5+ miles). In near-shore waters, 10-25 feet can be expected with occasional drops in visibility to 3-5 feet. In bays and rivers, visibility seldom exceeds 15 feet and zero visibility is not uncommon. Large changes in visibility with tides can be expected in the latter areas and up to 3 miles offshore near bays or rivers.

Strong tidal currents with rapid drops in visibility can be expected in the Chesapeake Bay and around the Outer Banks of North Carolina. Strong subsurface counter-currents in large rivers and bays have been encountered.

Stinging jellyfish are sometimes so abundant in estuaries that complete protection (including hands) is required. Gloves are recommended when working around rocks or structures due to the prevalence of sea urchins, oyster shells, stinging hydroids and barnacles. Sharks have been known to molest divers engaged in spearfishing.

Surf is generally moderate and most beaches are sand rather than rock, thus making entry from shore relatively easy.

9.1.3 Southeast

Waters off the Southeastern United States are, for the most part, tropical. Warm temperatures prevail, and can go as high as 75° to 80° F during the summer months. In the more northern portions of this region, off Georgia, a less tropical condition prevails. Water temperature during the summer in this area hovers around 70° F. During winter, water temperature in the southernmost areas stays

around 65° to 70° F; in the more northernly waters, however, temperatures drop as low as 50° to 55° F.

Visibility in the southern waters is good to excellent in the offshore areas; closer to shore, however, around shelves, it drops to 25 to 30 feet, and in harbors and bays, it can become poor. Farther north, visibility drops drastically both offshore and near shore and averages 20 to 25 feet.

When diving at the boundary of major oceanic current systems such as the Gulf Stream, special care must be exercised because of the episodic turbulent eddies that occasionally spin off the main mass of moving water. Extra care also must be taken because of the meandering nature of the current edge. A diver may encounter relatively quiet water at the beginning of a dive that will suddenly change into one of high current velocities with currents in excess of one knot. Dives in boundary regions must be planned to anticipate the possible encounter of high current speeds and appropriate surface support must be provided. Quite often there are sharp boundaries between water masses of different current velocities in the water column as the diver descends. Usually the current slows a foot or two above the bottom and if the diver hugs the bottom contours he can work unimpaired by the currents. However, the tending boat must be aware of the current differential and establish a reference to the diver's position or the boat may be carried away from the dive site. Dropping a well anchored buoy over the side at the beginning of the dive is a good means of establishing such a reference. Carefully monitoring the bubbles of the diver is extremely important in this type of diving. Some means of diver recall must be established in case the surface boat loses sight of the diver's position (See Paragraph 6.2.3).

9.1.4 Gulf of Mexico

Water temperature in the Gulf of Mexico drops to a low of about 56° during winter months and rises to about 86° F in the summer. Visibility offshore is generally good to excellent, with ranges around some reefs noted in excess of 100 feet. Visibility near shore is poor, particularly in the areas proximate to river outfalls, in bays and estuaries, and off some beaches. A mass of clear offshore water may move inshore and increase the visibility near shore up to 75 feet in regions southeast of Mobile. Currents in the Gulf are considered negligible

but are still a direct concern to divers as described in Paragraph 9.1.3. At times, significant currents are encountered around offshore oil platforms, and local knowledge must be relied upon. Weather conditions and resultant running seas are unpredictable. Unforecasted storms with 6- to 12-foot seas have, at times, quickly curtailed diving operations.

9.1.5 Northwest

Diving activities in the northwest range from southeast Alaska through Oregon.

Water temperatures in southeast Alaska range from around 34° to 38° F during winter months to an average of about 45° to 50° F during the summer. Serious consideration must be given to proper diving dress so that duration of a dive is not impaired by the effects of cold. During winter, temperature and wind conditions may combine such that some bays, inlets, and near shore waters will freeze

over.

Visibility in Alaskan waters varies drastically from place to place and from time to time. The best visibility is found along the outside coastlines and in the Aleutians where at best it may range from 40 to 80 feet. Visibility in inside waters of bays and straits is usually 15 to 20 feet. At any location visibility can become limited to 5 feet or less during intense phytoplankton blooms or storms. A condition develops late each spring in southeast Alaska where visibility in the upper 30 to 40 feet of the water column may be near zero due to phytoplankton, but below that layer the water may be very clear (visibility of 40 feet, or more). Although this deep, clear water is usually dark because of the shading effect of the overriding low visibility water, there is usually sufficient ambient light to work.

Currents and tides are strong and unpredictable in southeastern Alaskan waters. Tides are extremely heavy, and can cause currents as high as 10 knots in narrows. Currents also vary significantly and have been observed by divers to change direction within minutes.

Much of the Alaskan coastline is steep and rocky with many areas too steep to allow divers to either enter or leave the water. Entry and exit points must be carefully selected before a dive. Most sections of coastline are accessible only from boats. During times of heavy seas or swells many near shore diving locations become completely unworkable.

Alaskan waters harbor relatively few hazardous marine organisms. Those that cause divers the most physical damage are the urchins, barnacles, and jellyfishes with their respective potential for punctures, abrasions, and stings. Dense beds of kelp can cause some problems to divers, especially when swimming on the surface. Sharks and whales are common, but rarely, if ever, seen under water and generally would not influence diving activity in any way. Presence of killer whales, which are also common, might be an exception. Although no known diver/killer whale encounters have taken place in Alaska, general caution should keep divers out of the water if these animals are known to be near. Sea lions are very abundant in some areas of Alaska and although they are not known to have ever harmed a diver, they can psychologically upset a diver not accustomed to their presence under water. Sea lions are strongly attracted to divers and because of their large size, speed, and agility, and occasional bellowing rushes at divers, they can be disruptive to an otherwise routine dive.

Farther south, in the waters of Washington and Oregon, water temperatures range from about 43° to 60° F over the year in protected areas such as Puget Sound. In open ocean waters, depending on water masses moving through, temperatures ranging from 40° to 60° F may be encountered over the year. Visibility is usually low, ranging from 5 to 25 feet in coastal water near beaches and from zero to 70 feet in protected Puget Sound waters.

Currents, in certain areas, are strong and unpredictable. This is especially true in river diving, where very low visibility can result in orientation problems. Logs, stumps, wrecked automobiles, fishing hooks and lines, and similar bottom trash also pose distinct dangers to a river diver.

9.1.6 Mid-Pacific

The Mid-Pacific region includes the waters of Northern and Central California. Generally from San Francisco north, the best diving conditions occur from June through September, in terms of underwater visibility as well as water temperatures. From San Francisco south to Point Conception, good diving conditions may continue through December.

From San Francisco north to the Oregon border, summer temperatures generally range from about 18° to 56° F. Fall and early winter temperatures

from 52° to 60° F, and late winter and spring temperatures from 45° to 54° F. A thermocline generally exists at depths from 20 to 40 feet during late spring and summer. The difference in surface and bottom temperature during this period ranges between 2° and 5° F. A full wet suit, including hood, boots, and gloves is a necessity when diving in this area.

Visibility varies quite drastically throughout the area from summer to winter. From Fort Bragg to the Oregon border, late spring and summer visibility ranges between 10 and 15 feet. In the late summer and fall, underwater visibility increases to about 15 to 25 feet. During the winter and early spring, visibility decreases to 0 to 10 feet. South of Fort Bragg down to San Francisco visibility ranges from 10-20 feet increasing to 30 feet in the fall. From Santa Cruz north to San Francisco, visibility ranges from 5 to 15 feet in the early spring and summer, 10 to 25 feet in late summer and fall, and 0 to 10 feet during winter and early spring. From Point Conception to Santa Cruz visibility ranges from 15 to 25 feet during the late spring and summer to 15 to 50 feet in the fall and occasionally may reach 100 feet near Carmel Bay. During winter and early spring one can expect 5 to 20 foot visibility. The main factor controlling visibility in this area is the huge plankton bloom, which occurs during upwelling in the spring and summer and the dirty water conditions caused by rough seas and river runoffs during the winter and early spring.

Three species of surface canopy forming brown algae, kelp, occur on the Pacific coast. From Monterey north, the dominant kelp is the bull kelp. This particular species forms large beds but because of its structure, does not pose the same entanglement hazard to the diver as the giant kelp (See Paragraph 9.3.5).

Surf conditions north of Point Conception are probably the most important consideration in planning a dive. Even on calm days divers can expect two to three foot surf in most areas and on rough days it is not uncommon to see waves ten or more feet high. The diver should always scout the proposed diving area before going into the water to determine the safest area of entry and, if conditions should change, alternate exit sites (See Paragraph 13.1.1).

Long-shore currents and tidal currents are com mon and tend to be severe in northern and central California. Divers should especially watch for strong currents on very windy days around headlands,

offshore rocks, and reefs. Rip currents are very common along beaches and in coves.

Hazardous Marine Animals. As in other areas, the diver must watch for sea urchins, jellyfish, and rockfish. The latter because of venomous, anal, dorsal, and head spines. Shark attacks in this area are rare. During the last 15 to 20 years, less than two dozen attacks on divers have been recorded. There are, however, certain areas and conditions that seem to be correlated with potential shark attack. Diving around the Farallon Islands, Bodega Bay, Tomales Bay, and off San Francisco is not recommended except when underwater visibility is ideal. Stingrays and electric rays should be approached with caution; the former because of their puncture producing spine in the tail, and the latter because of the electric shock which they are capable of producing (See Section 15).

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There are five ecological reserves in this area, where all animals and plants are protected. One at Point Lobos State Reserve, one in the Point Reyes Seashore area, one in Salt Point State Park, in the Estero de Limantour Reserve in Marin County north of San Francisco and one at Del Mar Landing in Sonoma County. Divers should consult with the park authorities to determine the boundaries and restrictions in marine reserves.

9.1.7 Southwest

Waters of the Southwest include the area from Point Conception to the northern Baja Peninsula. Water temperatures range from 50° to 60° F in winter and 55° to 70° F in summer, with some locally colder areas due to upwelling. During much of the year, temperatures below 100 foot depths are fairly stable in the 50's and low 60's (°F). In fall and winter there is a great deal of mixing in the upper layers and no discrete temperature zonation is noted. However, a distinct summer thermocline at 40to 60-foot depths causes a sharp temperature drop and should be accounted for when planning dives.

Horizontal visibility ranges from 5 to 10 feet along much of the mainland coast to as much as 100 feet around the off-shore islands. Best visibility conditions are in the late summer and fall. During spring and early summer, visibility is generally less (30-50 feet around the islands), due in part to the prevailing overcasts and heavy fogs. Winter storm conditions and rain runoff can drop visibility to zero for miles along the mainland coast, as the prevailing longshore

current distributes suspended material from storm drains and river mouths.

Shore conditions along the southern California mainland coast range from sand beaches to high palisade cliffs. Ocean access from these areas is often impossible, and a careful check of charts and maps, supplemented by a preliminary entrance site visit, is highly recommended. The offshore islands are generally diveable only by boat. Moderate to heavy surf prevails along the entire mainland coast and on the windward sides of the offshore islands. Under certain weather conditions the normally calm leeward sides may also offer hazardous diving conditions.

Currents and tides are not of prime importance here, although there are local exceptions. Currents around the islands, especially during tidal changes, may attain speeds of 3 to 4 knots. The direction and relative strength of near-shore currents can be observed both topside and under water by watching the degree and direction of kelp layover.

Hazardous marine organisms include: sharks (especially around the offshore islands) such as blue, horned, swell, angel, and leopard; whales, killer whales, moray eels, sea urchins and jellyfishes. Divers should be aware of the appearance and locations of these species (See Section 15).

Sewer outfalls are common along the mainland coast, and direct contact with the effluent should be avoided. The discharge point may vary from a few hundred feet to several miles offshore, in from 60 to several hundred feet of water. The effluent may or may not reach the surface as a boil, in which temperatures are sharply elevated, paper and other debris is seen, and a definite odor is detected. If diving must be conducted in these areas, such precautions as extensive immunization, use of fullface diving gear, and scrupulous post-dive hygiene must be observed. Most discharge points are marked on charts and may be evidenced on the surface by the aforementioned boil and/or an orange and white striped spar buoy anchored near the pipe terminus.

As in Northern California, ecological reserves, with various restrictions, have been established. Inquiries can be made at the local offices of the California Department of Fish and Game for the locations and current restrictions.

Diving in northern Mexican (Upper Baja California) waters is similar to that in lower southern California. However, heavy fines and boat impound